diff --git a/Android.bp b/Android.bp
index f920782..0eb5fd9 100644
--- a/Android.bp
+++ b/Android.bp
@@ -76,7 +76,6 @@
 
         // external dependencies
         "libhealthhalutils",
-        "libfstab",
     ],
 }
 
@@ -150,7 +149,6 @@
 
     static_libs: [
         "libotautil",
-        "libfstab",
     ],
 
     init_rc: [
@@ -177,7 +175,6 @@
 
     static_libs: [
         "libotautil",
-        "libfstab",
     ],
 
     init_rc: [
diff --git a/CleanSpec.mk b/CleanSpec.mk
index a7ab0d9..6bd1eb1 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -51,6 +51,10 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/SHARED_LIBRARIES/libinstall.recovery_intermediates)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/recovery/root/system/lib64/libinstall.so)
 
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/data/nativetest/recovery_component_test)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/data/nativetest64/recovery_component_test)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/testcases/recovery_component_test)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/README.md b/README.md
index efcd318..0ccc10b 100644
--- a/README.md
+++ b/README.md
@@ -22,11 +22,9 @@
 
     # 32-bit device
     adb shell /data/nativetest/recovery_unit_test/recovery_unit_test
-    adb shell /data/nativetest/recovery_component_test/recovery_component_test
 
     # Or 64-bit device
     adb shell /data/nativetest64/recovery_unit_test/recovery_unit_test
-    adb shell /data/nativetest64/recovery_component_test/recovery_component_test
 
 Running the manual tests
 ------------------------
diff --git a/TEST_MAPPING b/TEST_MAPPING
new file mode 100644
index 0000000..a304582
--- /dev/null
+++ b/TEST_MAPPING
@@ -0,0 +1,14 @@
+{
+  "presubmit": [
+    {
+      "name": "minadbd_test"
+    },
+    {
+      "name": "recovery_unit_test"
+    },
+    {
+      "name": "recovery_host_test",
+      "host": true
+    }
+  ]
+}
diff --git a/applypatch/imgdiff.cpp b/applypatch/imgdiff.cpp
index 415d95f..6ad4a61 100644
--- a/applypatch/imgdiff.cpp
+++ b/applypatch/imgdiff.cpp
@@ -675,7 +675,7 @@
 // Iterate the zip entries and compose the image chunks accordingly.
 bool ZipModeImage::InitializeChunks(const std::string& filename, ZipArchiveHandle handle) {
   void* cookie;
-  int ret = StartIteration(handle, &cookie, nullptr, nullptr);
+  int ret = StartIteration(handle, &cookie);
   if (ret != 0) {
     LOG(ERROR) << "Failed to iterate over entries in " << filename << ": " << ErrorCodeString(ret);
     return false;
@@ -683,12 +683,11 @@
 
   // Create a list of deflated zip entries, sorted by offset.
   std::vector<std::pair<std::string, ZipEntry>> temp_entries;
-  ZipString name;
+  std::string name;
   ZipEntry entry;
   while ((ret = Next(cookie, &entry, &name)) == 0) {
     if (entry.method == kCompressDeflated || limit_ > 0) {
-      std::string entry_name(name.name, name.name + name.name_length);
-      temp_entries.emplace_back(entry_name, entry);
+      temp_entries.emplace_back(name, entry);
     }
   }
 
diff --git a/bootloader_message/Android.bp b/bootloader_message/Android.bp
index 450dad0..8d72a11 100644
--- a/bootloader_message/Android.bp
+++ b/bootloader_message/Android.bp
@@ -36,6 +36,18 @@
         "libbootloader_message_defaults",
     ],
     recovery_available: true,
+    host_supported: true,
+
+    target: {
+        host: {
+            shared_libs: [
+                "libcutils", // for strlcpy
+            ],
+        },
+        darwin: {
+            enabled: false,
+        },
+    }
 }
 
 cc_library_static {
diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
index c1ebeaa..e684abb 100644
--- a/bootloader_message/bootloader_message.cpp
+++ b/bootloader_message/bootloader_message.cpp
@@ -30,6 +30,10 @@
 #include <android-base/unique_fd.h>
 #include <fstab/fstab.h>
 
+#ifndef __ANDROID__
+#include <cutils/memory.h>  // for strlcpy
+#endif
+
 using android::fs_mgr::Fstab;
 using android::fs_mgr::ReadDefaultFstab;
 
@@ -179,6 +183,14 @@
   return write_bootloader_message(boot, err);
 }
 
+bool write_bootloader_message_to(const std::vector<std::string>& options,
+                                 const std::string& misc_blk_device, std::string* err) {
+  bootloader_message boot = {};
+  update_bootloader_message_in_struct(&boot, options);
+
+  return write_bootloader_message_to(boot, misc_blk_device, err);
+}
+
 bool update_bootloader_message(const std::vector<std::string>& options, std::string* err) {
   bootloader_message boot;
   if (!read_bootloader_message(&boot, err)) {
@@ -197,13 +209,15 @@
   memset(boot->recovery, 0, sizeof(boot->recovery));
 
   strlcpy(boot->command, "boot-recovery", sizeof(boot->command));
-  strlcpy(boot->recovery, "recovery\n", sizeof(boot->recovery));
+
+  std::string recovery = "recovery\n";
   for (const auto& s : options) {
-    strlcat(boot->recovery, s.c_str(), sizeof(boot->recovery));
+    recovery += s;
     if (s.back() != '\n') {
-      strlcat(boot->recovery, "\n", sizeof(boot->recovery));
+      recovery += '\n';
     }
   }
+  strlcpy(boot->recovery, recovery.c_str(), sizeof(boot->recovery));
   return true;
 }
 
diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h
index 95dd8f4..5c0a450 100644
--- a/bootloader_message/include/bootloader_message/bootloader_message.h
+++ b/bootloader_message/include/bootloader_message/bootloader_message.h
@@ -208,6 +208,11 @@
 // set the command and recovery fields, and reset the rest.
 bool write_bootloader_message(const std::vector<std::string>& options, std::string* err);
 
+// Write bootloader message (boots into recovery with the options) to the specific BCB device. Will
+// set the command and recovery fields, and reset the rest.
+bool write_bootloader_message_to(const std::vector<std::string>& options,
+                                 const std::string& misc_blk_device, std::string* err);
+
 // Update bootloader message (boots into recovery with the options) to BCB. Will
 // only update the command and recovery fields.
 bool update_bootloader_message(const std::vector<std::string>& options, std::string* err);
diff --git a/edify/expr.cpp b/edify/expr.cpp
index c090eb2..e5e0e24 100644
--- a/edify/expr.cpp
+++ b/edify/expr.cpp
@@ -421,5 +421,5 @@
   return nullptr;
 }
 
-State::State(const std::string& script, void* cookie)
-    : script(script), cookie(cookie), error_code(kNoError), cause_code(kNoCause) {}
+State::State(const std::string& script, UpdaterInterface* interface)
+    : script(script), updater(interface), error_code(kNoError), cause_code(kNoCause) {}
diff --git a/edify/include/edify/expr.h b/edify/include/edify/expr.h
index 5cbd5e1..cd9c701 100644
--- a/edify/include/edify/expr.h
+++ b/edify/include/edify/expr.h
@@ -23,19 +23,20 @@
 #include <string>
 #include <vector>
 
+#include "edify/updater_interface.h"
+
 // Forward declaration to avoid including "otautil/error_code.h".
 enum ErrorCode : int;
 enum CauseCode : int;
 
 struct State {
-  State(const std::string& script, void* cookie);
+  State(const std::string& script, UpdaterInterface* cookie);
 
   // The source of the original script.
   const std::string& script;
 
-  // Optional pointer to app-specific data; the core of edify never
-  // uses this value.
-  void* cookie;
+  // A pointer to app-specific data; the libedify doesn't use this value.
+  UpdaterInterface* updater;
 
   // The error message (if any) returned if the evaluation aborts.
   // Should be empty initially, will be either empty or a string that
diff --git a/edify/include/edify/updater_interface.h b/edify/include/edify/updater_interface.h
new file mode 100644
index 0000000..a4d581e
--- /dev/null
+++ b/edify/include/edify/updater_interface.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#include <string>
+#include <string_view>
+
+struct ZipArchive;
+typedef ZipArchive* ZipArchiveHandle;
+
+class UpdaterRuntimeInterface;
+
+class UpdaterInterface {
+ public:
+  virtual ~UpdaterInterface() = default;
+
+  // Writes the message to command pipe, adds a new line in the end.
+  virtual void WriteToCommandPipe(const std::string_view message, bool flush = false) const = 0;
+
+  // Sends over the message to recovery to print it on the screen.
+  virtual void UiPrint(const std::string_view message) const = 0;
+
+  // Given the name of the block device, returns |name| for updates on the device; or the file path
+  // to the fake block device for simulations.
+  virtual std::string FindBlockDeviceName(const std::string_view name) const = 0;
+
+  virtual UpdaterRuntimeInterface* GetRuntime() const = 0;
+  virtual ZipArchiveHandle GetPackageHandle() const = 0;
+  virtual std::string GetResult() const = 0;
+  virtual uint8_t* GetMappedPackageAddress() const = 0;
+};
diff --git a/edify/include/edify/updater_runtime_interface.h b/edify/include/edify/updater_runtime_interface.h
new file mode 100644
index 0000000..15ccd83
--- /dev/null
+++ b/edify/include/edify/updater_runtime_interface.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <string>
+#include <string_view>
+#include <vector>
+
+// This class serves as the base to updater runtime. It wraps the runtime dependent functions; and
+// updates on device and host simulations can have different implementations. e.g. block devices
+// during host simulation merely a temporary file. With this class, the caller side in registered
+// updater's functions will stay the same for both update and simulation.
+class UpdaterRuntimeInterface {
+ public:
+  virtual ~UpdaterRuntimeInterface() = default;
+
+  // Returns true if it's a runtime instance for simulation.
+  virtual bool IsSimulator() const = 0;
+
+  // Returns the value of system property |key|. If the property doesn't exist, returns
+  // |default_value|.
+  virtual std::string GetProperty(const std::string_view key,
+                                  const std::string_view default_value) const = 0;
+
+  // Given the name of the block device, returns |name| for updates on the device; or the file path
+  // to the fake block device for simulations.
+  virtual std::string FindBlockDeviceName(const std::string_view name) const = 0;
+
+  // Mounts the |location| on |mount_point|. Returns 0 on success.
+  virtual int Mount(const std::string_view location, const std::string_view mount_point,
+                    const std::string_view fs_type, const std::string_view mount_options) = 0;
+
+  // Returns true if |mount_point| is mounted.
+  virtual bool IsMounted(const std::string_view mount_point) const = 0;
+
+  // Unmounts the |mount_point|. Returns a pair of results with the first value indicating
+  // if the |mount_point| is mounted, and the second value indicating the result of umount(2).
+  virtual std::pair<bool, int> Unmount(const std::string_view mount_point) = 0;
+
+  // Reads |filename| and puts its value to |content|.
+  virtual bool ReadFileToString(const std::string_view filename, std::string* content) const = 0;
+
+  // Updates the content of |filename| with |content|.
+  virtual bool WriteStringToFile(const std::string_view content,
+                                 const std::string_view filename) const = 0;
+
+  // Wipes the first |len| bytes of block device in |filename|.
+  virtual int WipeBlockDevice(const std::string_view filename, size_t len) const = 0;
+
+  // Starts a child process and runs the program with |args|. Uses vfork(2) if |is_vfork| is true.
+  virtual int RunProgram(const std::vector<std::string>& args, bool is_vfork) const = 0;
+
+  // Runs tune2fs with arguments |args|.
+  virtual int Tune2Fs(const std::vector<std::string>& args) const = 0;
+};
\ No newline at end of file
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index 14f5e4b..2023349 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -30,10 +30,10 @@
 #include "recovery_ui/ui.h"
 
 static const std::vector<std::pair<std::string, Device::BuiltinAction>> kFastbootMenuActions{
-  { "Reboot system now", Device::REBOOT },
+  { "Reboot system now", Device::REBOOT_FROM_FASTBOOT },
   { "Enter recovery", Device::ENTER_RECOVERY },
   { "Reboot to bootloader", Device::REBOOT_BOOTLOADER },
-  { "Power off", Device::SHUTDOWN },
+  { "Power off", Device::SHUTDOWN_FROM_FASTBOOT },
 };
 
 Device::BuiltinAction StartFastboot(Device* device, const std::vector<std::string>& /* args */) {
diff --git a/fsck_unshare_blocks.cpp b/fsck_unshare_blocks.cpp
index e74f8ba..9dc0fd8 100644
--- a/fsck_unshare_blocks.cpp
+++ b/fsck_unshare_blocks.cpp
@@ -34,7 +34,7 @@
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/unique_fd.h>
-#include <fstab/fstab.h>
+#include <fs_mgr/roots.h>
 
 #include "otautil/roots.h"
 
@@ -120,7 +120,7 @@
   std::vector<std::string> partitions = { "/odm", "/oem", "/product", "/vendor" };
 
   // Temporarily mount system so we can copy e2fsck_static.
-  std::string system_root = get_system_root();
+  auto system_root = android::fs_mgr::GetSystemRoot();
   bool mounted = ensure_path_mounted_at(system_root, "/mnt/system") != -1;
   partitions.push_back(system_root);
 
diff --git a/fuse_sideload/Android.bp b/fuse_sideload/Android.bp
index 8548548..9bf19eb 100644
--- a/fuse_sideload/Android.bp
+++ b/fuse_sideload/Android.bp
@@ -34,6 +34,10 @@
         "include",
     ],
 
+    static_libs: [
+        "libotautil",
+    ],
+
     shared_libs: [
         "libbase",
         "libcrypto",
diff --git a/fuse_sideload/fuse_provider.cpp b/fuse_sideload/fuse_provider.cpp
index 58786f5..5ee6e24 100644
--- a/fuse_sideload/fuse_provider.cpp
+++ b/fuse_sideload/fuse_provider.cpp
@@ -27,8 +27,11 @@
 #include <functional>
 
 #include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/strings.h>
 
 #include "fuse_sideload.h"
+#include "otautil/sysutil.h"
 
 FuseFileDataProvider::FuseFileDataProvider(const std::string& path, uint32_t block_size) {
   struct stat sb;
@@ -69,3 +72,79 @@
 void FuseFileDataProvider::Close() {
   fd_.reset();
 }
+
+FuseBlockDataProvider::FuseBlockDataProvider(uint64_t file_size, uint32_t fuse_block_size,
+                                             android::base::unique_fd&& fd,
+                                             uint32_t source_block_size, RangeSet ranges)
+    : FuseDataProvider(file_size, fuse_block_size),
+      fd_(std::move(fd)),
+      source_block_size_(source_block_size),
+      ranges_(std::move(ranges)) {
+  // Make sure the offset is also aligned with the blocks on the block device when we call
+  // ReadBlockAlignedData().
+  CHECK_EQ(0, fuse_block_size_ % source_block_size_);
+}
+
+bool FuseBlockDataProvider::ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
+                                                 uint32_t start_block) const {
+  uint64_t offset = static_cast<uint64_t>(start_block) * fuse_block_size_;
+  if (fetch_size > file_size_ || offset > file_size_ - fetch_size) {
+    LOG(ERROR) << "Out of bound read, offset: " << offset << ", fetch size: " << fetch_size
+               << ", file size " << file_size_;
+    return false;
+  }
+
+  auto read_ranges =
+      ranges_.GetSubRanges(offset / source_block_size_, fetch_size / source_block_size_);
+  if (!read_ranges) {
+    return false;
+  }
+
+  uint8_t* next_out = buffer;
+  for (const auto& [range_start, range_end] : read_ranges.value()) {
+    uint64_t bytes_start = static_cast<uint64_t>(range_start) * source_block_size_;
+    uint64_t bytes_to_read = static_cast<uint64_t>(range_end - range_start) * source_block_size_;
+    if (!android::base::ReadFullyAtOffset(fd_, next_out, bytes_to_read, bytes_start)) {
+      PLOG(ERROR) << "Failed to read " << bytes_to_read << " bytes at offset " << bytes_start;
+      return false;
+    }
+
+    next_out += bytes_to_read;
+  }
+
+  if (uint64_t tailing_bytes = fetch_size % source_block_size_; tailing_bytes != 0) {
+    // Calculate the offset to last partial block.
+    uint64_t tailing_offset =
+        read_ranges.value()
+            ? static_cast<uint64_t>((read_ranges->cend() - 1)->second) * source_block_size_
+            : static_cast<uint64_t>(start_block) * source_block_size_;
+    if (!android::base::ReadFullyAtOffset(fd_, next_out, tailing_bytes, tailing_offset)) {
+      PLOG(ERROR) << "Failed to read tailing " << tailing_bytes << " bytes at offset "
+                  << tailing_offset;
+      return false;
+    }
+  }
+  return true;
+}
+
+std::unique_ptr<FuseBlockDataProvider> FuseBlockDataProvider::CreateFromBlockMap(
+    const std::string& block_map_path, uint32_t fuse_block_size) {
+  auto block_map = BlockMapData::ParseBlockMapFile(block_map_path);
+  if (!block_map) {
+    return nullptr;
+  }
+
+  android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(block_map.path().c_str(), O_RDONLY)));
+  if (fd == -1) {
+    PLOG(ERROR) << "Failed to open " << block_map.path();
+    return nullptr;
+  }
+
+  return std::unique_ptr<FuseBlockDataProvider>(
+      new FuseBlockDataProvider(block_map.file_size(), fuse_block_size, std::move(fd),
+                                block_map.block_size(), block_map.block_ranges()));
+}
+
+void FuseBlockDataProvider::Close() {
+  fd_.reset();
+}
diff --git a/fuse_sideload/include/fuse_provider.h b/fuse_sideload/include/fuse_provider.h
index 59059cf..8d4ea40 100644
--- a/fuse_sideload/include/fuse_provider.h
+++ b/fuse_sideload/include/fuse_provider.h
@@ -18,10 +18,13 @@
 
 #include <stdint.h>
 
+#include <memory>
 #include <string>
 
 #include <android-base/unique_fd.h>
 
+#include "otautil/rangeset.h"
+
 // This is the base class to read data from source and provide the data to FUSE.
 class FuseDataProvider {
  public:
@@ -70,3 +73,28 @@
   // The underlying source to read data from.
   android::base::unique_fd fd_;
 };
+
+// This class parses a block map and reads data from the underlying block device.
+class FuseBlockDataProvider : public FuseDataProvider {
+ public:
+  // Constructs the fuse provider from the block map.
+  static std::unique_ptr<FuseBlockDataProvider> CreateFromBlockMap(
+      const std::string& block_map_path, uint32_t fuse_block_size);
+
+  RangeSet ranges() const {
+    return ranges_;
+  }
+  bool ReadBlockAlignedData(uint8_t* buffer, uint32_t fetch_size,
+                            uint32_t start_block) const override;
+  void Close() override;
+
+ private:
+  FuseBlockDataProvider(uint64_t file_size, uint32_t fuse_block_size, android::base::unique_fd&& fd,
+                        uint32_t source_block_size, RangeSet ranges);
+  // The underlying block device to read data from.
+  android::base::unique_fd fd_;
+  // The block size of the source block device.
+  uint32_t source_block_size_;
+  // The block ranges from the source block device that consist of the file
+  RangeSet ranges_;
+};
diff --git a/install/Android.bp b/install/Android.bp
index ea893a0..4696e50 100644
--- a/install/Android.bp
+++ b/install/Android.bp
@@ -47,7 +47,6 @@
         // external dependencies
         "libvintf_recovery",
         "libvintf",
-        "libfstab",
     ],
 }
 
@@ -67,6 +66,7 @@
         "package.cpp",
         "verifier.cpp",
         "wipe_data.cpp",
+        "wipe_device.cpp",
     ],
 
     shared_libs: [
diff --git a/install/adb_install.cpp b/install/adb_install.cpp
index 4dd1f1b..2de1075 100644
--- a/install/adb_install.cpp
+++ b/install/adb_install.cpp
@@ -90,7 +90,7 @@
 
 // Installs the package from FUSE. Returns the installation result and whether it should continue
 // waiting for new commands.
-static auto AdbInstallPackageHandler(RecoveryUI* ui, int* result) {
+static auto AdbInstallPackageHandler(RecoveryUI* ui, InstallResult* result) {
   // How long (in seconds) we wait for the package path to be ready. It doesn't need to be too long
   // because the minadbd service has already issued an install command. FUSE_SIDELOAD_HOST_PATHNAME
   // will start to exist once the host connects and starts serving a package. Poll for its
@@ -110,7 +110,7 @@
         break;
       }
     }
-    *result = install_package(FUSE_SIDELOAD_HOST_PATHNAME, false, false, 0, ui);
+    *result = InstallPackage(FUSE_SIDELOAD_HOST_PATHNAME, false, false, 0, ui);
     break;
   }
 
@@ -120,7 +120,7 @@
   return std::make_pair(*result == INSTALL_SUCCESS, should_continue);
 }
 
-static auto AdbRebootHandler(MinadbdCommand command, int* result,
+static auto AdbRebootHandler(MinadbdCommand command, InstallResult* result,
                              Device::BuiltinAction* reboot_action) {
   // Use Device::REBOOT_{FASTBOOT,RECOVERY,RESCUE}, instead of the ones with ENTER_. This allows
   // rebooting back into fastboot/recovery/rescue mode through bootloader, which may use a newly
@@ -331,7 +331,7 @@
   signal(SIGPIPE, SIG_DFL);
 }
 
-int ApplyFromAdb(Device* device, bool rescue_mode, Device::BuiltinAction* reboot_action) {
+InstallResult ApplyFromAdb(Device* device, bool rescue_mode, Device::BuiltinAction* reboot_action) {
   // Save the usb state to restore after the sideload operation.
   std::string usb_state = android::base::GetProperty("sys.usb.state", "none");
   // Clean up state and stop adbd.
@@ -342,7 +342,7 @@
 
   RecoveryUI* ui = device->GetUI();
 
-  int install_result = INSTALL_ERROR;
+  InstallResult install_result = INSTALL_ERROR;
   std::map<MinadbdCommand, CommandFunction> command_map{
     { MinadbdCommand::kInstall, std::bind(&AdbInstallPackageHandler, ui, &install_result) },
     { MinadbdCommand::kRebootAndroid, std::bind(&AdbRebootHandler, MinadbdCommand::kRebootAndroid,
diff --git a/install/fuse_sdcard_install.cpp b/install/fuse_sdcard_install.cpp
index 1aa8768..a5caa6e 100644
--- a/install/fuse_sdcard_install.cpp
+++ b/install/fuse_sdcard_install.cpp
@@ -133,7 +133,7 @@
   return run_fuse_sideload(std::move(file_data_reader)) == 0;
 }
 
-int ApplyFromSdcard(Device* device, RecoveryUI* ui) {
+InstallResult ApplyFromSdcard(Device* device, RecoveryUI* ui) {
   if (ensure_path_mounted(SDCARD_ROOT) != 0) {
     LOG(ERROR) << "\n-- Couldn't mount " << SDCARD_ROOT << ".\n";
     return INSTALL_ERROR;
@@ -159,9 +159,8 @@
     _exit(status ? EXIT_SUCCESS : EXIT_FAILURE);
   }
 
-  // FUSE_SIDELOAD_HOST_PATHNAME will start to exist once the fuse in child
-  // process is ready.
-  int result = INSTALL_ERROR;
+  // FUSE_SIDELOAD_HOST_PATHNAME will start to exist once the fuse in child process is ready.
+  InstallResult result = INSTALL_ERROR;
   int status;
   bool waited = false;
   for (int i = 0; i < SDCARD_INSTALL_TIMEOUT; ++i) {
@@ -184,7 +183,7 @@
       }
     }
 
-    result = install_package(FUSE_SIDELOAD_HOST_PATHNAME, false, false, 0 /*retry_count*/, ui);
+    result = InstallPackage(FUSE_SIDELOAD_HOST_PATHNAME, false, false, 0 /* retry_count */, ui);
     break;
   }
 
diff --git a/install/include/install/adb_install.h b/install/include/install/adb_install.h
index 3a0a817..8800223 100644
--- a/install/include/install/adb_install.h
+++ b/install/include/install/adb_install.h
@@ -16,9 +16,10 @@
 
 #pragma once
 
-#include <recovery_ui/device.h>
+#include "install/install.h"
+#include "recovery_ui/device.h"
 
-// Applies a package via `adb sideload` or `adb rescue`. Returns the install result (in `enum
-// InstallResult`). When a reboot has been requested, INSTALL_REBOOT will be the return value, with
-// the reboot target set in reboot_action.
-int ApplyFromAdb(Device* device, bool rescue_mode, Device::BuiltinAction* reboot_action);
+// Applies a package via `adb sideload` or `adb rescue`. Returns the install result. When a reboot
+// has been requested, INSTALL_REBOOT will be the return value, with the reboot target set in
+// reboot_action.
+InstallResult ApplyFromAdb(Device* device, bool rescue_mode, Device::BuiltinAction* reboot_action);
diff --git a/install/include/install/fuse_sdcard_install.h b/install/include/install/fuse_sdcard_install.h
index d9214ca..e5bb01f 100644
--- a/install/include/install/fuse_sdcard_install.h
+++ b/install/include/install/fuse_sdcard_install.h
@@ -16,7 +16,8 @@
 
 #pragma once
 
+#include "install/install.h"
 #include "recovery_ui/device.h"
 #include "recovery_ui/ui.h"
 
-int ApplyFromSdcard(Device* device, RecoveryUI* ui);
+InstallResult ApplyFromSdcard(Device* device, RecoveryUI* ui);
diff --git a/install/include/install/install.h b/install/include/install/install.h
index c0a8f1f..44a5cde 100644
--- a/install/include/install/install.h
+++ b/install/include/install/install.h
@@ -47,8 +47,8 @@
 // Installs the given update package. This function should also wipe the cache partition after a
 // successful installation if |should_wipe_cache| is true or an updater command asks to wipe the
 // cache.
-int install_package(const std::string& package, bool should_wipe_cache, bool needs_mount,
-                    int retry_count, RecoveryUI* ui);
+InstallResult InstallPackage(const std::string& package, bool should_wipe_cache, bool needs_mount,
+                             int retry_count, RecoveryUI* ui);
 
 // Verifies the package by ota keys. Returns true if the package is verified successfully,
 // otherwise returns false.
@@ -58,14 +58,11 @@
 // result to |metadata|. Return true if succeed, otherwise return false.
 bool ReadMetadataFromPackage(ZipArchiveHandle zip, std::map<std::string, std::string>* metadata);
 
-// Reads the "recovery.wipe" entry in the zip archive returns a list of partitions to wipe.
-std::vector<std::string> GetWipePartitionList(Package* wipe_package);
-
 // Verifies the compatibility info in a Treble-compatible package. Returns true directly if the
 // entry doesn't exist.
 bool verify_package_compatibility(ZipArchiveHandle package_zip);
 
-// Checks if the the metadata in the OTA package has expected values. Returns 0 on success.
-// Mandatory checks: ota-type, pre-device and serial number(if presents)
-// AB OTA specific checks: pre-build version, fingerprint, timestamp.
-int CheckPackageMetadata(const std::map<std::string, std::string>& metadata, OtaType ota_type);
+// Checks if the metadata in the OTA package has expected values. Mandatory checks: ota-type,
+// pre-device and serial number (if presents). A/B OTA specific checks: pre-build version,
+// fingerprint, timestamp.
+bool CheckPackageMetadata(const std::map<std::string, std::string>& metadata, OtaType ota_type);
diff --git a/install/include/install/wipe_device.h b/install/include/install/wipe_device.h
new file mode 100644
index 0000000..c60b999
--- /dev/null
+++ b/install/include/install/wipe_device.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "install/package.h"
+#include "recovery_ui/device.h"
+
+// Wipes the current A/B device, with a secure wipe of all the partitions in RECOVERY_WIPE.
+bool WipeAbDevice(Device* device, size_t wipe_package_size);
+
+// Reads the "recovery.wipe" entry in the zip archive returns a list of partitions to wipe.
+std::vector<std::string> GetWipePartitionList(Package* wipe_package);
diff --git a/install/include/private/setup_commands.h b/install/include/private/setup_commands.h
index 7fdc741..dcff761 100644
--- a/install/include/private/setup_commands.h
+++ b/install/include/private/setup_commands.h
@@ -27,13 +27,13 @@
 // |zip| located at |package|. Stores the command line that should be called into |cmd|. The
 // |status_fd| is the file descriptor the child process should use to report back the progress of
 // the update.
-int SetUpNonAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int retry_count,
-                             int status_fd, std::vector<std::string>* cmd);
+bool SetUpNonAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int retry_count,
+                              int status_fd, std::vector<std::string>* cmd);
 
 // Sets up the commands for an A/B update. Extracts the needed entries from the open zip archive
 // |zip| located at |package|. Stores the command line that should be called into |cmd|. The
 // |status_fd| is the file descriptor the child process should use to report back the progress of
 // the update. Note that since this applies to the sideloading flow only, it takes one less
 // parameter |retry_count| than the non-A/B version.
-int SetUpAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int status_fd,
-                          std::vector<std::string>* cmd);
+bool SetUpAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int status_fd,
+                           std::vector<std::string>* cmd);
diff --git a/install/install.cpp b/install/install.cpp
index e2d4700..8d46641 100644
--- a/install/install.cpp
+++ b/install/install.cpp
@@ -73,9 +73,8 @@
   CHECK(metadata != nullptr);
 
   static constexpr const char* METADATA_PATH = "META-INF/com/android/metadata";
-  ZipString path(METADATA_PATH);
   ZipEntry entry;
-  if (FindEntry(zip, path, &entry) != 0) {
+  if (FindEntry(zip, METADATA_PATH, &entry) != 0) {
     LOG(ERROR) << "Failed to find " << METADATA_PATH;
     return false;
   }
@@ -139,14 +138,14 @@
 // Checks the build version, fingerprint and timestamp in the metadata of the A/B package.
 // Downgrading is not allowed unless explicitly enabled in the package and only for
 // incremental packages.
-static int CheckAbSpecificMetadata(const std::map<std::string, std::string>& metadata) {
+static bool CheckAbSpecificMetadata(const std::map<std::string, std::string>& metadata) {
   // Incremental updates should match the current build.
   auto device_pre_build = android::base::GetProperty("ro.build.version.incremental", "");
   auto pkg_pre_build = get_value(metadata, "pre-build-incremental");
   if (!pkg_pre_build.empty() && pkg_pre_build != device_pre_build) {
     LOG(ERROR) << "Package is for source build " << pkg_pre_build << " but expected "
                << device_pre_build;
-    return INSTALL_ERROR;
+    return false;
   }
 
   auto device_fingerprint = android::base::GetProperty("ro.build.fingerprint", "");
@@ -154,7 +153,7 @@
   if (!pkg_pre_build_fingerprint.empty() && pkg_pre_build_fingerprint != device_fingerprint) {
     LOG(ERROR) << "Package is for source build " << pkg_pre_build_fingerprint << " but expected "
                << device_fingerprint;
-    return INSTALL_ERROR;
+    return false;
   }
 
   // Check for downgrade version.
@@ -172,36 +171,36 @@
                     "newer than timestamp "
                  << build_timestamp << " but package has timestamp " << pkg_post_timestamp
                  << " and downgrade not allowed.";
-      return INSTALL_ERROR;
+      return false;
     }
     if (pkg_pre_build_fingerprint.empty()) {
       LOG(ERROR) << "Downgrade package must have a pre-build version set, not allowed.";
-      return INSTALL_ERROR;
+      return false;
     }
   }
 
-  return 0;
+  return true;
 }
 
-int CheckPackageMetadata(const std::map<std::string, std::string>& metadata, OtaType ota_type) {
+bool CheckPackageMetadata(const std::map<std::string, std::string>& metadata, OtaType ota_type) {
   auto package_ota_type = get_value(metadata, "ota-type");
   auto expected_ota_type = OtaTypeToString(ota_type);
   if (ota_type != OtaType::AB && ota_type != OtaType::BRICK) {
     LOG(INFO) << "Skip package metadata check for ota type " << expected_ota_type;
-    return 0;
+    return true;
   }
 
   if (package_ota_type != expected_ota_type) {
     LOG(ERROR) << "Unexpected ota package type, expects " << expected_ota_type << ", actual "
                << package_ota_type;
-    return INSTALL_ERROR;
+    return false;
   }
 
   auto device = android::base::GetProperty("ro.product.device", "");
   auto pkg_device = get_value(metadata, "pre-device");
   if (pkg_device != device || pkg_device.empty()) {
     LOG(ERROR) << "Package is for product " << pkg_device << " but expected " << device;
-    return INSTALL_ERROR;
+    return false;
   }
 
   // We allow the package to not have any serialno; and we also allow it to carry multiple serial
@@ -218,7 +217,7 @@
     }
     if (!serial_number_match) {
       LOG(ERROR) << "Package is for serial " << pkg_serial_no;
-      return INSTALL_ERROR;
+      return false;
     }
   }
 
@@ -226,21 +225,20 @@
     return CheckAbSpecificMetadata(metadata);
   }
 
-  return 0;
+  return true;
 }
 
-int SetUpAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int status_fd,
-                          std::vector<std::string>* cmd) {
+bool SetUpAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int status_fd,
+                           std::vector<std::string>* cmd) {
   CHECK(cmd != nullptr);
 
   // For A/B updates we extract the payload properties to a buffer and obtain the RAW payload offset
   // in the zip file.
   static constexpr const char* AB_OTA_PAYLOAD_PROPERTIES = "payload_properties.txt";
-  ZipString property_name(AB_OTA_PAYLOAD_PROPERTIES);
   ZipEntry properties_entry;
-  if (FindEntry(zip, property_name, &properties_entry) != 0) {
+  if (FindEntry(zip, AB_OTA_PAYLOAD_PROPERTIES, &properties_entry) != 0) {
     LOG(ERROR) << "Failed to find " << AB_OTA_PAYLOAD_PROPERTIES;
-    return INSTALL_CORRUPT;
+    return false;
   }
   uint32_t properties_entry_length = properties_entry.uncompressed_length;
   std::vector<uint8_t> payload_properties(properties_entry_length);
@@ -248,15 +246,14 @@
       ExtractToMemory(zip, &properties_entry, payload_properties.data(), properties_entry_length);
   if (err != 0) {
     LOG(ERROR) << "Failed to extract " << AB_OTA_PAYLOAD_PROPERTIES << ": " << ErrorCodeString(err);
-    return INSTALL_CORRUPT;
+    return false;
   }
 
   static constexpr const char* AB_OTA_PAYLOAD = "payload.bin";
-  ZipString payload_name(AB_OTA_PAYLOAD);
   ZipEntry payload_entry;
-  if (FindEntry(zip, payload_name, &payload_entry) != 0) {
+  if (FindEntry(zip, AB_OTA_PAYLOAD, &payload_entry) != 0) {
     LOG(ERROR) << "Failed to find " << AB_OTA_PAYLOAD;
-    return INSTALL_CORRUPT;
+    return false;
   }
   long payload_offset = payload_entry.offset;
   *cmd = {
@@ -266,20 +263,19 @@
     "--headers=" + std::string(payload_properties.begin(), payload_properties.end()),
     android::base::StringPrintf("--status_fd=%d", status_fd),
   };
-  return 0;
+  return true;
 }
 
-int SetUpNonAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int retry_count,
-                             int status_fd, std::vector<std::string>* cmd) {
+bool SetUpNonAbUpdateCommands(const std::string& package, ZipArchiveHandle zip, int retry_count,
+                              int status_fd, std::vector<std::string>* cmd) {
   CHECK(cmd != nullptr);
 
   // In non-A/B updates we extract the update binary from the package.
   static constexpr const char* UPDATE_BINARY_NAME = "META-INF/com/google/android/update-binary";
-  ZipString binary_name(UPDATE_BINARY_NAME);
   ZipEntry binary_entry;
-  if (FindEntry(zip, binary_name, &binary_entry) != 0) {
+  if (FindEntry(zip, UPDATE_BINARY_NAME, &binary_entry) != 0) {
     LOG(ERROR) << "Failed to find update binary " << UPDATE_BINARY_NAME;
-    return INSTALL_CORRUPT;
+    return false;
   }
 
   const std::string binary_path = Paths::Get().temporary_update_binary();
@@ -288,13 +284,12 @@
       open(binary_path.c_str(), O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, 0755));
   if (fd == -1) {
     PLOG(ERROR) << "Failed to create " << binary_path;
-    return INSTALL_ERROR;
+    return false;
   }
 
-  int32_t error = ExtractEntryToFile(zip, &binary_entry, fd);
-  if (error != 0) {
+  if (auto error = ExtractEntryToFile(zip, &binary_entry, fd); error != 0) {
     LOG(ERROR) << "Failed to extract " << UPDATE_BINARY_NAME << ": " << ErrorCodeString(error);
-    return INSTALL_ERROR;
+    return false;
   }
 
   // When executing the update binary contained in the package, the arguments passed are:
@@ -311,7 +306,7 @@
   if (retry_count > 0) {
     cmd->push_back("retry");
   }
-  return 0;
+  return true;
 }
 
 static void log_max_temperature(int* max_temperature, const std::atomic<bool>& logger_finished) {
@@ -325,9 +320,9 @@
 }
 
 // If the package contains an update binary, extract it and run it.
-static int try_update_binary(const std::string& package, ZipArchiveHandle zip, bool* wipe_cache,
-                             std::vector<std::string>* log_buffer, int retry_count,
-                             int* max_temperature, RecoveryUI* ui) {
+static InstallResult TryUpdateBinary(const std::string& package, ZipArchiveHandle zip,
+                                     bool* wipe_cache, std::vector<std::string>* log_buffer,
+                                     int retry_count, int* max_temperature, RecoveryUI* ui) {
   std::map<std::string, std::string> metadata;
   if (!ReadMetadataFromPackage(zip, &metadata)) {
     LOG(ERROR) << "Failed to parse metadata in the zip file";
@@ -335,11 +330,10 @@
   }
 
   bool is_ab = android::base::GetBoolProperty("ro.build.ab_update", false);
-  // Verifies against the metadata in the package first.
-  if (int check_status = is_ab ? CheckPackageMetadata(metadata, OtaType::AB) : 0;
-      check_status != 0) {
+  // Verify against the metadata in the package first.
+  if (is_ab && !CheckPackageMetadata(metadata, OtaType::AB)) {
     log_buffer->push_back(android::base::StringPrintf("error: %d", kUpdateBinaryCommandFailure));
-    return check_status;
+    return INSTALL_ERROR;
   }
 
   ReadSourceTargetBuild(metadata, log_buffer);
@@ -386,12 +380,12 @@
   //
 
   std::vector<std::string> args;
-  if (int update_status =
+  if (auto setup_result =
           is_ab ? SetUpAbUpdateCommands(package, zip, pipe_write.get(), &args)
                 : SetUpNonAbUpdateCommands(package, zip, retry_count, pipe_write.get(), &args);
-      update_status != 0) {
+      !setup_result) {
     log_buffer->push_back(android::base::StringPrintf("error: %d", kUpdateBinaryCommandFailure));
-    return update_status;
+    return INSTALL_CORRUPT;
   }
 
   pid_t pid = fork();
@@ -510,9 +504,8 @@
   LOG(INFO) << "Verifying package compatibility...";
 
   static constexpr const char* COMPATIBILITY_ZIP_ENTRY = "compatibility.zip";
-  ZipString compatibility_entry_name(COMPATIBILITY_ZIP_ENTRY);
   ZipEntry compatibility_entry;
-  if (FindEntry(package_zip, compatibility_entry_name, &compatibility_entry) != 0) {
+  if (FindEntry(package_zip, COMPATIBILITY_ZIP_ENTRY, &compatibility_entry) != 0) {
     LOG(INFO) << "Package doesn't contain " << COMPATIBILITY_ZIP_ENTRY << " entry";
     return true;
   }
@@ -536,7 +529,7 @@
 
   // Iterate all the entries inside COMPATIBILITY_ZIP_ENTRY and read the contents.
   void* cookie;
-  ret = StartIteration(zip_handle, &cookie, nullptr, nullptr);
+  ret = StartIteration(zip_handle, &cookie);
   if (ret != 0) {
     LOG(ERROR) << "Failed to start iterating zip entries: " << ErrorCodeString(ret);
     CloseArchive(zip_handle);
@@ -546,13 +539,13 @@
 
   std::vector<std::string> compatibility_info;
   ZipEntry info_entry;
-  ZipString info_name;
+  std::string info_name;
   while (Next(cookie, &info_entry, &info_name) == 0) {
     std::string content(info_entry.uncompressed_length, '\0');
     int32_t ret = ExtractToMemory(zip_handle, &info_entry, reinterpret_cast<uint8_t*>(&content[0]),
                                   info_entry.uncompressed_length);
     if (ret != 0) {
-      LOG(ERROR) << "Failed to read " << info_name.name << ": " << ErrorCodeString(ret);
+      LOG(ERROR) << "Failed to read " << info_name << ": " << ErrorCodeString(ret);
       CloseArchive(zip_handle);
       return false;
     }
@@ -571,9 +564,10 @@
   return false;
 }
 
-static int really_install_package(const std::string& path, bool* wipe_cache, bool needs_mount,
-                                  std::vector<std::string>* log_buffer, int retry_count,
-                                  int* max_temperature, RecoveryUI* ui) {
+static InstallResult VerifyAndInstallPackage(const std::string& path, bool* wipe_cache,
+                                             bool needs_mount, std::vector<std::string>* log_buffer,
+                                             int retry_count, int* max_temperature,
+                                             RecoveryUI* ui) {
   ui->SetBackground(RecoveryUI::INSTALLING_UPDATE);
   ui->Print("Finding update package...\n");
   // Give verification half the progress bar...
@@ -624,16 +618,16 @@
     ui->Print("Retry attempt: %d\n", retry_count);
   }
   ui->SetEnableReboot(false);
-  int result =
-      try_update_binary(path, zip, wipe_cache, log_buffer, retry_count, max_temperature, ui);
+  auto result =
+      TryUpdateBinary(path, zip, wipe_cache, log_buffer, retry_count, max_temperature, ui);
   ui->SetEnableReboot(true);
   ui->Print("\n");
 
   return result;
 }
 
-int install_package(const std::string& path, bool should_wipe_cache, bool needs_mount,
-                    int retry_count, RecoveryUI* ui) {
+InstallResult InstallPackage(const std::string& path, bool should_wipe_cache, bool needs_mount,
+                             int retry_count, RecoveryUI* ui) {
   CHECK(!path.empty());
 
   auto start = std::chrono::system_clock::now();
@@ -641,15 +635,15 @@
   int start_temperature = GetMaxValueFromThermalZone();
   int max_temperature = start_temperature;
 
-  int result;
+  InstallResult result;
   std::vector<std::string> log_buffer;
   if (setup_install_mounts() != 0) {
     LOG(ERROR) << "failed to set up expected mounts for install; aborting";
     result = INSTALL_ERROR;
   } else {
     bool updater_wipe_cache = false;
-    result = really_install_package(path, &updater_wipe_cache, needs_mount, &log_buffer,
-                                    retry_count, &max_temperature, ui);
+    result = VerifyAndInstallPackage(path, &updater_wipe_cache, needs_mount, &log_buffer,
+                                     retry_count, &max_temperature, ui);
     should_wipe_cache = should_wipe_cache || updater_wipe_cache;
   }
 
diff --git a/install/verifier.cpp b/install/verifier.cpp
index 6ba1d77..02759cd 100644
--- a/install/verifier.cpp
+++ b/install/verifier.cpp
@@ -311,8 +311,7 @@
 
 static std::vector<Certificate> IterateZipEntriesAndSearchForKeys(const ZipArchiveHandle& handle) {
   void* cookie;
-  ZipString suffix("x509.pem");
-  int32_t iter_status = StartIteration(handle, &cookie, nullptr, &suffix);
+  int32_t iter_status = StartIteration(handle, &cookie, "", "x509.pem");
   if (iter_status != 0) {
     LOG(ERROR) << "Failed to iterate over entries in the certificate zipfile: "
                << ErrorCodeString(iter_status);
@@ -321,22 +320,21 @@
 
   std::vector<Certificate> result;
 
-  ZipString name;
+  std::string name;
   ZipEntry entry;
   while ((iter_status = Next(cookie, &entry, &name)) == 0) {
     std::vector<uint8_t> pem_content(entry.uncompressed_length);
     if (int32_t extract_status =
             ExtractToMemory(handle, &entry, pem_content.data(), pem_content.size());
         extract_status != 0) {
-      LOG(ERROR) << "Failed to extract " << std::string(name.name, name.name + name.name_length);
+      LOG(ERROR) << "Failed to extract " << name;
       return {};
     }
 
     Certificate cert(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
     // Aborts the parsing if we fail to load one of the key file.
     if (!LoadCertificateFromBuffer(pem_content, &cert)) {
-      LOG(ERROR) << "Failed to load keys from "
-                 << std::string(name.name, name.name + name.name_length);
+      LOG(ERROR) << "Failed to load keys from " << name;
       return {};
     }
 
diff --git a/install/wipe_device.cpp b/install/wipe_device.cpp
new file mode 100644
index 0000000..89d5d31
--- /dev/null
+++ b/install/wipe_device.cpp
@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "install/wipe_device.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fs.h>
+#include <stdint.h>
+#include <sys/ioctl.h>
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <ziparchive/zip_archive.h>
+
+#include "bootloader_message/bootloader_message.h"
+#include "install/install.h"
+#include "install/package.h"
+#include "recovery_ui/device.h"
+#include "recovery_ui/ui.h"
+
+std::vector<std::string> GetWipePartitionList(Package* wipe_package) {
+  ZipArchiveHandle zip = wipe_package->GetZipArchiveHandle();
+  if (!zip) {
+    LOG(ERROR) << "Failed to get ZipArchiveHandle";
+    return {};
+  }
+
+  constexpr char RECOVERY_WIPE_ENTRY_NAME[] = "recovery.wipe";
+
+  std::string partition_list_content;
+  ZipEntry entry;
+  if (FindEntry(zip, RECOVERY_WIPE_ENTRY_NAME, &entry) == 0) {
+    uint32_t length = entry.uncompressed_length;
+    partition_list_content = std::string(length, '\0');
+    if (auto err = ExtractToMemory(
+            zip, &entry, reinterpret_cast<uint8_t*>(partition_list_content.data()), length);
+        err != 0) {
+      LOG(ERROR) << "Failed to extract " << RECOVERY_WIPE_ENTRY_NAME << ": "
+                 << ErrorCodeString(err);
+      return {};
+    }
+  } else {
+    LOG(INFO) << "Failed to find " << RECOVERY_WIPE_ENTRY_NAME
+              << ", falling back to use the partition list on device.";
+
+    constexpr char RECOVERY_WIPE_ON_DEVICE[] = "/etc/recovery.wipe";
+    if (!android::base::ReadFileToString(RECOVERY_WIPE_ON_DEVICE, &partition_list_content)) {
+      PLOG(ERROR) << "failed to read \"" << RECOVERY_WIPE_ON_DEVICE << "\"";
+      return {};
+    }
+  }
+
+  std::vector<std::string> result;
+  auto lines = android::base::Split(partition_list_content, "\n");
+  for (const auto& line : lines) {
+    auto partition = android::base::Trim(line);
+    // Ignore '#' comment or empty lines.
+    if (android::base::StartsWith(partition, "#") || partition.empty()) {
+      continue;
+    }
+    result.push_back(line);
+  }
+
+  return result;
+}
+
+// Secure-wipes a given partition. It uses BLKSECDISCARD, if supported. Otherwise, it goes with
+// BLKDISCARD (if device supports BLKDISCARDZEROES) or BLKZEROOUT.
+static bool SecureWipePartition(const std::string& partition) {
+  android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(partition.c_str(), O_WRONLY)));
+  if (fd == -1) {
+    PLOG(ERROR) << "Failed to open \"" << partition << "\"";
+    return false;
+  }
+
+  uint64_t range[2] = { 0, 0 };
+  if (ioctl(fd, BLKGETSIZE64, &range[1]) == -1 || range[1] == 0) {
+    PLOG(ERROR) << "Failed to get partition size";
+    return false;
+  }
+  LOG(INFO) << "Secure-wiping \"" << partition << "\" from " << range[0] << " to " << range[1];
+
+  LOG(INFO) << "  Trying BLKSECDISCARD...";
+  if (ioctl(fd, BLKSECDISCARD, &range) == -1) {
+    PLOG(WARNING) << "  Failed";
+
+    // Use BLKDISCARD if it zeroes out blocks, otherwise use BLKZEROOUT.
+    unsigned int zeroes;
+    if (ioctl(fd, BLKDISCARDZEROES, &zeroes) == 0 && zeroes != 0) {
+      LOG(INFO) << "  Trying BLKDISCARD...";
+      if (ioctl(fd, BLKDISCARD, &range) == -1) {
+        PLOG(ERROR) << "  Failed";
+        return false;
+      }
+    } else {
+      LOG(INFO) << "  Trying BLKZEROOUT...";
+      if (ioctl(fd, BLKZEROOUT, &range) == -1) {
+        PLOG(ERROR) << "  Failed";
+        return false;
+      }
+    }
+  }
+
+  LOG(INFO) << "  Done";
+  return true;
+}
+
+static std::unique_ptr<Package> ReadWipePackage(size_t wipe_package_size) {
+  if (wipe_package_size == 0) {
+    LOG(ERROR) << "wipe_package_size is zero";
+    return nullptr;
+  }
+
+  std::string wipe_package;
+  if (std::string err_str; !read_wipe_package(&wipe_package, wipe_package_size, &err_str)) {
+    PLOG(ERROR) << "Failed to read wipe package" << err_str;
+    return nullptr;
+  }
+
+  return Package::CreateMemoryPackage(
+      std::vector<uint8_t>(wipe_package.begin(), wipe_package.end()), nullptr);
+}
+
+// Checks if the wipe package matches expectation. If the check passes, reads the list of
+// partitions to wipe from the package. Checks include
+// 1. verify the package.
+// 2. check metadata (ota-type, pre-device and serial number if having one).
+static bool CheckWipePackage(Package* wipe_package, RecoveryUI* ui) {
+  if (!verify_package(wipe_package, ui)) {
+    LOG(ERROR) << "Failed to verify package";
+    return false;
+  }
+
+  ZipArchiveHandle zip = wipe_package->GetZipArchiveHandle();
+  if (!zip) {
+    LOG(ERROR) << "Failed to get ZipArchiveHandle";
+    return false;
+  }
+
+  std::map<std::string, std::string> metadata;
+  if (!ReadMetadataFromPackage(zip, &metadata)) {
+    LOG(ERROR) << "Failed to parse metadata in the zip file";
+    return false;
+  }
+
+  return CheckPackageMetadata(metadata, OtaType::BRICK);
+}
+
+bool WipeAbDevice(Device* device, size_t wipe_package_size) {
+  auto ui = device->GetUI();
+  ui->SetBackground(RecoveryUI::ERASING);
+  ui->SetProgressType(RecoveryUI::INDETERMINATE);
+
+  auto wipe_package = ReadWipePackage(wipe_package_size);
+  if (!wipe_package) {
+    LOG(ERROR) << "Failed to open wipe package";
+    return false;
+  }
+
+  if (!CheckWipePackage(wipe_package.get(), ui)) {
+    LOG(ERROR) << "Failed to verify wipe package";
+    return false;
+  }
+
+  auto partition_list = GetWipePartitionList(wipe_package.get());
+  if (partition_list.empty()) {
+    LOG(ERROR) << "Empty wipe ab partition list";
+    return false;
+  }
+
+  for (const auto& partition : partition_list) {
+    // Proceed anyway even if it fails to wipe some partition.
+    SecureWipePartition(partition);
+  }
+  return true;
+}
diff --git a/minadbd/Android.bp b/minadbd/Android.bp
index 007e505..afd57ad 100644
--- a/minadbd/Android.bp
+++ b/minadbd/Android.bp
@@ -43,6 +43,10 @@
         "minadbd_services.cpp",
     ],
 
+    static_libs: [
+        "libotautil",
+    ],
+
     shared_libs: [
         "libadbd",
         "libbase",
@@ -96,6 +100,7 @@
     static_libs: [
         "libminadbd_services",
         "libfusesideload",
+        "libotautil",
         "libadbd",
         "libcrypto",
     ],
diff --git a/minadbd/minadbd_services.cpp b/minadbd/minadbd_services.cpp
index 68f940c..1e6eb31 100644
--- a/minadbd/minadbd_services.cpp
+++ b/minadbd/minadbd_services.cpp
@@ -247,7 +247,7 @@
 
 unique_fd daemon_service_to_fd(std::string_view name, atransport* /* transport */) {
   // Common services that are supported both in sideload and rescue modes.
-  if (ConsumePrefix(&name, "reboot:")) {
+  if (android::base::ConsumePrefix(&name, "reboot:")) {
     // "reboot:<target>", where target must be one of the following.
     std::string args(name);
     if (args.empty() || args == "bootloader" || args == "rescue" || args == "recovery" ||
@@ -260,17 +260,17 @@
 
   // Rescue-specific services.
   if (rescue_mode) {
-    if (ConsumePrefix(&name, "rescue-install:")) {
+    if (android::base::ConsumePrefix(&name, "rescue-install:")) {
       // rescue-install:<file-size>:<block-size>
       std::string args(name);
       return create_service_thread(
           "rescue-install", std::bind(RescueInstallHostService, std::placeholders::_1, args));
-    } else if (ConsumePrefix(&name, "rescue-getprop:")) {
+    } else if (android::base::ConsumePrefix(&name, "rescue-getprop:")) {
       // rescue-getprop:<prop>
       std::string args(name);
       return create_service_thread(
           "rescue-getprop", std::bind(RescueGetpropHostService, std::placeholders::_1, args));
-    } else if (ConsumePrefix(&name, "rescue-wipe:")) {
+    } else if (android::base::ConsumePrefix(&name, "rescue-wipe:")) {
       // rescue-wipe:target:<message-size>
       std::string args(name);
       return create_service_thread("rescue-wipe",
@@ -285,7 +285,7 @@
     // This exit status causes recovery to print a special error message saying to use a newer adb
     // (that supports sideload-host).
     exit(kMinadbdAdbVersionError);
-  } else if (ConsumePrefix(&name, "sideload-host:")) {
+  } else if (android::base::ConsumePrefix(&name, "sideload-host:")) {
     // sideload-host:<file-size>:<block-size>
     std::string args(name);
     return create_service_thread("sideload-host",
diff --git a/minui/resources.cpp b/minui/resources.cpp
index 069a495..00d36d5 100644
--- a/minui/resources.cpp
+++ b/minui/resources.cpp
@@ -347,6 +347,10 @@
   // match the locale string without the {script} section.
   // For instance, prefix == "en" matches locale == "en-US", prefix == "sr-Latn" matches locale
   // == "sr-Latn-BA", and prefix == "zh-CN" matches locale == "zh-Hans-CN".
+  if (prefix.empty()) {
+    return false;
+  }
+
   if (android::base::StartsWith(locale, prefix)) {
     return true;
   }
@@ -414,12 +418,18 @@
     __unused int len = row[4];
     char* loc = reinterpret_cast<char*>(&row[5]);
 
-    if (y + 1 + h >= height || matches_locale(loc, locale)) {
+    // We need to include one additional line for the metadata of the localized image.
+    if (y + 1 + h > height) {
+      printf("Read exceeds the image boundary, y %u, h %d, height %u\n", y, h, height);
+      return -8;
+    }
+
+    if (matches_locale(loc, locale)) {
       printf("  %20s: %s (%d x %d @ %d)\n", name, loc, w, h, y);
 
       auto surface = GRSurface::Create(w, h, w, 1);
       if (!surface) {
-        return -8;
+        return -9;
       }
 
       for (int i = 0; i < h; ++i, ++y) {
@@ -428,7 +438,7 @@
       }
 
       *pSurface = surface.release();
-      break;
+      return 0;
     }
 
     for (int i = 0; i < h; ++i, ++y) {
@@ -436,7 +446,7 @@
     }
   }
 
-  return 0;
+  return -10;
 }
 
 void res_free_surface(GRSurface* surface) {
diff --git a/otautil/Android.bp b/otautil/Android.bp
index 0a21731..871dcae 100644
--- a/otautil/Android.bp
+++ b/otautil/Android.bp
@@ -24,12 +24,16 @@
 
     // Minimal set of files to support host build.
     srcs: [
+        "dirutil.cpp",
         "paths.cpp",
         "rangeset.cpp",
+        "sysutil.cpp",
     ],
 
     shared_libs: [
         "libbase",
+        "libcutils",
+        "libselinux",
     ],
 
     export_include_dirs: [
@@ -39,12 +43,10 @@
     target: {
         android: {
             srcs: [
-                "dirutil.cpp",
                 "logging.cpp",
                 "mounts.cpp",
                 "parse_install_logs.cpp",
                 "roots.cpp",
-                "sysutil.cpp",
                 "thermalutil.cpp",
             ],
 
@@ -57,10 +59,12 @@
             ],
 
             shared_libs: [
-                "libcutils",
                 "libext4_utils",
                 "libfs_mgr",
-                "libselinux",
+            ],
+
+            export_static_lib_headers: [
+                "libfstab",
             ],
         },
     },
diff --git a/otautil/include/otautil/rangeset.h b/otautil/include/otautil/rangeset.h
index e91d02c..a18c30e 100644
--- a/otautil/include/otautil/rangeset.h
+++ b/otautil/include/otautil/rangeset.h
@@ -18,6 +18,7 @@
 
 #include <stddef.h>
 
+#include <optional>
 #include <string>
 #include <utility>
 #include <vector>
@@ -49,6 +50,12 @@
   // bounds. For example, "3,5" contains blocks 3 and 4. So "3,5" and "5,7" are not overlapped.
   bool Overlaps(const RangeSet& other) const;
 
+  // Returns a subset of ranges starting from |start_index| with respect to the original range. The
+  // output range will have |num_of_blocks| blocks in size. Returns std::nullopt if the input is
+  // invalid. e.g. RangeSet({{0, 5}, {10, 15}}).GetSubRanges(1, 5) returns
+  // RangeSet({{1, 5}, {10, 11}}).
+  std::optional<RangeSet> GetSubRanges(size_t start_index, size_t num_of_blocks) const;
+
   // Returns a vector of RangeSets that contain the same set of blocks represented by the current
   // RangeSet. The RangeSets in the vector contain similar number of blocks, with a maximum delta
   // of 1-block between any two of them. For example, 14 blocks would be split into 4 + 4 + 3 + 3,
diff --git a/otautil/include/otautil/roots.h b/otautil/include/otautil/roots.h
index 482f3d0..2ab3f45 100644
--- a/otautil/include/otautil/roots.h
+++ b/otautil/include/otautil/roots.h
@@ -53,7 +53,3 @@
 // Ensure that all and only the volumes that packages expect to find
 // mounted (/tmp and /cache) are mounted.  Returns 0 on success.
 int setup_install_mounts();
-
-bool logical_partitions_mapped();
-
-std::string get_system_root();
diff --git a/otautil/include/otautil/sysutil.h b/otautil/include/otautil/sysutil.h
index 692a99e..326db86 100644
--- a/otautil/include/otautil/sysutil.h
+++ b/otautil/include/otautil/sysutil.h
@@ -14,12 +14,12 @@
  * limitations under the License.
  */
 
-#ifndef _OTAUTIL_SYSUTIL
-#define _OTAUTIL_SYSUTIL
+#pragma once
 
 #include <sys/types.h>
 
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include "rangeset.h"
@@ -101,13 +101,14 @@
   std::vector<MappedRange> ranges_;
 };
 
-// Wrapper function to trigger a reboot, by additionally handling quiescent reboot mode. The
-// command should start with "reboot," (e.g. "reboot,bootloader" or "reboot,").
-bool reboot(const std::string& command);
+// Reboots the device into the specified target, by additionally handling quiescent reboot mode.
+// All unknown targets reboot into Android.
+bool Reboot(std::string_view target);
+
+// Triggers a shutdown.
+bool Shutdown(std::string_view target);
 
 // Returns a null-terminated char* array, where the elements point to the C-strings in the given
 // vector, plus an additional nullptr at the end. This is a helper function that facilitates
 // calling C functions (such as getopt(3)) that expect an array of C-strings.
 std::vector<char*> StringVectorToNullTerminatedArray(const std::vector<std::string>& args);
-
-#endif  // _OTAUTIL_SYSUTIL
diff --git a/otautil/rangeset.cpp b/otautil/rangeset.cpp
index 5ab8e08..8ee99dd 100644
--- a/otautil/rangeset.cpp
+++ b/otautil/rangeset.cpp
@@ -184,6 +184,58 @@
   return false;
 }
 
+std::optional<RangeSet> RangeSet::GetSubRanges(size_t start_index, size_t num_of_blocks) const {
+  size_t end_index = start_index + num_of_blocks;  // The index of final block to read plus one
+  if (start_index > end_index || end_index > blocks_) {
+    LOG(ERROR) << "Failed to get the sub ranges for start_index " << start_index
+               << " num_of_blocks " << num_of_blocks
+               << " total number of blocks the range contains is " << blocks_;
+    return std::nullopt;
+  }
+
+  if (num_of_blocks == 0) {
+    LOG(WARNING) << "num_of_blocks is zero when calling GetSubRanges()";
+    return RangeSet();
+  }
+
+  RangeSet result;
+  size_t current_index = 0;
+  for (const auto& [range_start, range_end] : ranges_) {
+    CHECK_LT(range_start, range_end);
+    size_t blocks_in_range = range_end - range_start;
+    // Linear search to skip the ranges until we reach start_block.
+    if (current_index + blocks_in_range <= start_index) {
+      current_index += blocks_in_range;
+      continue;
+    }
+
+    size_t trimmed_range_start = range_start;
+    // We have found the first block range to read, trim the heading blocks.
+    if (current_index < start_index) {
+      trimmed_range_start += start_index - current_index;
+    }
+    // Trim the trailing blocks if the last range has more blocks than desired; also return the
+    // result.
+    if (current_index + blocks_in_range >= end_index) {
+      size_t trimmed_range_end = range_end - (current_index + blocks_in_range - end_index);
+      if (!result.PushBack({ trimmed_range_start, trimmed_range_end })) {
+        return std::nullopt;
+      }
+
+      return result;
+    }
+
+    if (!result.PushBack({ trimmed_range_start, range_end })) {
+      return std::nullopt;
+    }
+    current_index += blocks_in_range;
+  }
+
+  LOG(ERROR) << "Failed to construct byte ranges to read, start_block: " << start_index
+             << ", num_of_blocks: " << num_of_blocks << " total number of blocks: " << blocks_;
+  return std::nullopt;
+}
+
 // Ranges in the the set should be mutually exclusive; and they're sorted by the start block.
 SortedRangeSet::SortedRangeSet(std::vector<Range>&& pairs) : RangeSet(std::move(pairs)) {
   std::sort(ranges_.begin(), ranges_.end());
diff --git a/otautil/roots.cpp b/otautil/roots.cpp
index 815d644..a778e05 100644
--- a/otautil/roots.cpp
+++ b/otautil/roots.cpp
@@ -275,11 +275,3 @@
   }
   return 0;
 }
-
-bool logical_partitions_mapped() {
-  return android::fs_mgr::LogicalPartitionsMapped();
-}
-
-std::string get_system_root() {
-  return android::fs_mgr::GetSystemRoot();
-}
diff --git a/otautil/sysutil.cpp b/otautil/sysutil.cpp
index 8366fa0..a882985 100644
--- a/otautil/sysutil.cpp
+++ b/otautil/sysutil.cpp
@@ -94,6 +94,11 @@
     remaining_blocks -= range_blocks;
   }
 
+  if (remaining_blocks != 0) {
+    LOG(ERROR) << "Invalid ranges: remaining blocks " << remaining_blocks;
+    return {};
+  }
+
   return BlockMapData(block_dev, file_size, blksize, std::move(ranges));
 }
 
@@ -214,14 +219,21 @@
   ranges_.clear();
 }
 
-bool reboot(const std::string& command) {
-  std::string cmd = command;
-  if (android::base::GetBoolProperty("ro.boot.quiescent", false)) {
+bool Reboot(std::string_view target) {
+  std::string cmd = "reboot," + std::string(target);
+  // Honor the quiescent mode if applicable.
+  if (target != "bootloader" && target != "fastboot" &&
+      android::base::GetBoolProperty("ro.boot.quiescent", false)) {
     cmd += ",quiescent";
   }
   return android::base::SetProperty(ANDROID_RB_PROPERTY, cmd);
 }
 
+bool Shutdown(std::string_view target) {
+  std::string cmd = "shutdown," + std::string(target);
+  return android::base::SetProperty(ANDROID_RB_PROPERTY, cmd);
+}
+
 std::vector<char*> StringVectorToNullTerminatedArray(const std::vector<std::string>& args) {
   std::vector<char*> result(args.size());
   std::transform(args.cbegin(), args.cend(), result.begin(),
diff --git a/recovery.cpp b/recovery.cpp
index 5fc673e..eb0c2b2 100644
--- a/recovery.cpp
+++ b/recovery.cpp
@@ -18,11 +18,9 @@
 
 #include <ctype.h>
 #include <errno.h>
-#include <fcntl.h>
 #include <getopt.h>
 #include <inttypes.h>
 #include <limits.h>
-#include <linux/fs.h>
 #include <linux/input.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -30,8 +28,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-#include <algorithm>
 #include <functional>
+#include <iterator>
 #include <memory>
 #include <string>
 #include <vector>
@@ -42,12 +40,12 @@
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
-#include <android-base/unique_fd.h>
-#include <bootloader_message/bootloader_message.h>
 #include <cutils/properties.h> /* for property_list */
+#include <fs_mgr/roots.h>
 #include <healthhalutils/HealthHalUtils.h>
 #include <ziparchive/zip_archive.h>
 
+#include "bootloader_message/bootloader_message.h"
 #include "common.h"
 #include "fsck_unshare_blocks.h"
 #include "install/adb_install.h"
@@ -55,6 +53,7 @@
 #include "install/install.h"
 #include "install/package.h"
 #include "install/wipe_data.h"
+#include "install/wipe_device.h"
 #include "otautil/error_code.h"
 #include "otautil/logging.h"
 #include "otautil/paths.h"
@@ -115,12 +114,12 @@
  * 3. main system reboots into recovery
  * 4. get_args() writes BCB with "boot-recovery" and "--update_package=..."
  *    -- after this, rebooting will attempt to reinstall the update --
- * 5. install_package() attempts to install the update
+ * 5. InstallPackage() attempts to install the update
  *    NOTE: the package install must itself be restartable from any point
  * 6. finish_recovery() erases BCB
  *    -- after this, rebooting will (try to) restart the main system --
  * 7. ** if install failed **
- *    7a. prompt_and_wait() shows an error icon and waits for the user
+ *    7a. PromptAndWait() shows an error icon and waits for the user
  *    7b. the user reboots (pulling the battery, etc) into the main system
  */
 
@@ -221,165 +220,6 @@
   }
 }
 
-// Secure-wipe a given partition. It uses BLKSECDISCARD, if supported. Otherwise, it goes with
-// BLKDISCARD (if device supports BLKDISCARDZEROES) or BLKZEROOUT.
-static bool secure_wipe_partition(const std::string& partition) {
-  android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(partition.c_str(), O_WRONLY)));
-  if (fd == -1) {
-    PLOG(ERROR) << "Failed to open \"" << partition << "\"";
-    return false;
-  }
-
-  uint64_t range[2] = { 0, 0 };
-  if (ioctl(fd, BLKGETSIZE64, &range[1]) == -1 || range[1] == 0) {
-    PLOG(ERROR) << "Failed to get partition size";
-    return false;
-  }
-  LOG(INFO) << "Secure-wiping \"" << partition << "\" from " << range[0] << " to " << range[1];
-
-  LOG(INFO) << "  Trying BLKSECDISCARD...";
-  if (ioctl(fd, BLKSECDISCARD, &range) == -1) {
-    PLOG(WARNING) << "  Failed";
-
-    // Use BLKDISCARD if it zeroes out blocks, otherwise use BLKZEROOUT.
-    unsigned int zeroes;
-    if (ioctl(fd, BLKDISCARDZEROES, &zeroes) == 0 && zeroes != 0) {
-      LOG(INFO) << "  Trying BLKDISCARD...";
-      if (ioctl(fd, BLKDISCARD, &range) == -1) {
-        PLOG(ERROR) << "  Failed";
-        return false;
-      }
-    } else {
-      LOG(INFO) << "  Trying BLKZEROOUT...";
-      if (ioctl(fd, BLKZEROOUT, &range) == -1) {
-        PLOG(ERROR) << "  Failed";
-        return false;
-      }
-    }
-  }
-
-  LOG(INFO) << "  Done";
-  return true;
-}
-
-static std::unique_ptr<Package> ReadWipePackage(size_t wipe_package_size) {
-  if (wipe_package_size == 0) {
-    LOG(ERROR) << "wipe_package_size is zero";
-    return nullptr;
-  }
-
-  std::string wipe_package;
-  std::string err_str;
-  if (!read_wipe_package(&wipe_package, wipe_package_size, &err_str)) {
-    PLOG(ERROR) << "Failed to read wipe package" << err_str;
-    return nullptr;
-  }
-
-  return Package::CreateMemoryPackage(
-      std::vector<uint8_t>(wipe_package.begin(), wipe_package.end()), nullptr);
-}
-
-// Checks if the wipe package matches expectation. If the check passes, reads the list of
-// partitions to wipe from the package. Checks include
-// 1. verify the package.
-// 2. check metadata (ota-type, pre-device and serial number if having one).
-static bool CheckWipePackage(Package* wipe_package) {
-  if (!verify_package(wipe_package, ui)) {
-    LOG(ERROR) << "Failed to verify package";
-    return false;
-  }
-
-  ZipArchiveHandle zip = wipe_package->GetZipArchiveHandle();
-  if (!zip) {
-    LOG(ERROR) << "Failed to get ZipArchiveHandle";
-    return false;
-  }
-
-  std::map<std::string, std::string> metadata;
-  if (!ReadMetadataFromPackage(zip, &metadata)) {
-    LOG(ERROR) << "Failed to parse metadata in the zip file";
-    return false;
-  }
-
-  return CheckPackageMetadata(metadata, OtaType::BRICK) == 0;
-}
-
-std::vector<std::string> GetWipePartitionList(Package* wipe_package) {
-  ZipArchiveHandle zip = wipe_package->GetZipArchiveHandle();
-  if (!zip) {
-    LOG(ERROR) << "Failed to get ZipArchiveHandle";
-    return {};
-  }
-
-  static constexpr const char* RECOVERY_WIPE_ENTRY_NAME = "recovery.wipe";
-
-  std::string partition_list_content;
-  ZipString path(RECOVERY_WIPE_ENTRY_NAME);
-  ZipEntry entry;
-  if (FindEntry(zip, path, &entry) == 0) {
-    uint32_t length = entry.uncompressed_length;
-    partition_list_content = std::string(length, '\0');
-    if (auto err = ExtractToMemory(
-            zip, &entry, reinterpret_cast<uint8_t*>(partition_list_content.data()), length);
-        err != 0) {
-      LOG(ERROR) << "Failed to extract " << RECOVERY_WIPE_ENTRY_NAME << ": "
-                 << ErrorCodeString(err);
-      return {};
-    }
-  } else {
-    LOG(INFO) << "Failed to find " << RECOVERY_WIPE_ENTRY_NAME
-              << ", falling back to use the partition list on device.";
-
-    static constexpr const char* RECOVERY_WIPE_ON_DEVICE = "/etc/recovery.wipe";
-    if (!android::base::ReadFileToString(RECOVERY_WIPE_ON_DEVICE, &partition_list_content)) {
-      PLOG(ERROR) << "failed to read \"" << RECOVERY_WIPE_ON_DEVICE << "\"";
-      return {};
-    }
-  }
-
-  std::vector<std::string> result;
-  std::vector<std::string> lines = android::base::Split(partition_list_content, "\n");
-  for (const std::string& line : lines) {
-    std::string partition = android::base::Trim(line);
-    // Ignore '#' comment or empty lines.
-    if (android::base::StartsWith(partition, "#") || partition.empty()) {
-      continue;
-    }
-    result.push_back(line);
-  }
-
-  return result;
-}
-
-// Wipes the current A/B device, with a secure wipe of all the partitions in RECOVERY_WIPE.
-static bool wipe_ab_device(size_t wipe_package_size) {
-  ui->SetBackground(RecoveryUI::ERASING);
-  ui->SetProgressType(RecoveryUI::INDETERMINATE);
-
-  auto wipe_package = ReadWipePackage(wipe_package_size);
-  if (!wipe_package) {
-    LOG(ERROR) << "Failed to open wipe package";
-    return false;
-  }
-
-  if (!CheckWipePackage(wipe_package.get())) {
-    LOG(ERROR) << "Failed to verify wipe package";
-    return false;
-  }
-
-  auto partition_list = GetWipePartitionList(wipe_package.get());
-  if (partition_list.empty()) {
-    LOG(ERROR) << "Empty wipe ab partition list";
-    return false;
-  }
-
-  for (const auto& partition : partition_list) {
-    // Proceed anyway even if it fails to wipe some partition.
-    secure_wipe_partition(partition);
-  }
-  return true;
-}
-
 static void choose_recovery_file(Device* device) {
   std::vector<std::string> entries;
   if (has_cache) {
@@ -473,14 +313,18 @@
   ui->ShowText(true);
 }
 
-// Returns REBOOT, SHUTDOWN, or REBOOT_BOOTLOADER. Returning NO_ACTION means to take the default,
-// which is to reboot or shutdown depending on if the --shutdown_after flag was passed to recovery.
-static Device::BuiltinAction prompt_and_wait(Device* device, int status) {
+// Shows the recovery UI and waits for user input. Returns one of the device builtin actions, such
+// as REBOOT, SHUTDOWN, or REBOOT_BOOTLOADER. Returning NO_ACTION means to take the default, which
+// is to reboot or shutdown depending on if the --shutdown_after flag was passed to recovery.
+static Device::BuiltinAction PromptAndWait(Device* device, InstallResult status) {
   for (;;) {
     finish_recovery();
     switch (status) {
       case INSTALL_SUCCESS:
       case INSTALL_NONE:
+      case INSTALL_SKIPPED:
+      case INSTALL_RETRY:
+      case INSTALL_KEY_INTERRUPTED:
         ui->SetBackground(RecoveryUI::NO_COMMAND);
         break;
 
@@ -488,6 +332,12 @@
       case INSTALL_CORRUPT:
         ui->SetBackground(RecoveryUI::ERROR);
         break;
+
+      case INSTALL_REBOOT:
+        // All the reboots should have been handled prior to entering PromptAndWait() or immediately
+        // after installing a package.
+        LOG(FATAL) << "Invalid status code of INSTALL_REBOOT";
+        break;
     }
     ui->SetProgressType(RecoveryUI::EMPTY);
 
@@ -506,6 +356,8 @@
             : device->InvokeMenuItem(chosen_item);
 
     switch (chosen_action) {
+      case Device::REBOOT_FROM_FASTBOOT:    // Can not happen
+      case Device::SHUTDOWN_FROM_FASTBOOT:  // Can not happen
       case Device::NO_ACTION:
         break;
 
@@ -588,8 +440,7 @@
         break;
       }
       case Device::MOUNT_SYSTEM:
-        // the system partition is mounted at /mnt/system
-        if (ensure_path_mounted_at(get_system_root(), "/mnt/system") != -1) {
+        if (ensure_path_mounted_at(android::fs_mgr::GetSystemRoot(), "/mnt/system") != -1) {
           ui->Print("Mounted /system.\n");
         }
         break;
@@ -851,7 +702,7 @@
 
   ui->Print("Supported API: %d\n", kRecoveryApiVersion);
 
-  int status = INSTALL_SUCCESS;
+  InstallResult status = INSTALL_SUCCESS;
   // next_action indicates the next target to reboot into upon finishing the install. It could be
   // overridden to a different reboot target per user request.
   Device::BuiltinAction next_action = shutdown_after ? Device::SHUTDOWN : Device::REBOOT;
@@ -881,7 +732,7 @@
         set_retry_bootloader_message(retry_count + 1, args);
       }
 
-      status = install_package(update_package, should_wipe_cache, true, retry_count, ui);
+      status = InstallPackage(update_package, should_wipe_cache, true, retry_count, ui);
       if (status != INSTALL_SUCCESS) {
         ui->Print("Installation aborted.\n");
 
@@ -895,8 +746,8 @@
           // Print retry count on screen.
           ui->Print("Retry attempt %d\n", retry_count);
 
-          // Reboot and retry the update
-          if (!reboot("reboot,recovery")) {
+          // Reboot back into recovery to retry the update.
+          if (!Reboot("recovery")) {
             ui->Print("Reboot failed\n");
           } else {
             while (true) {
@@ -934,7 +785,7 @@
       status = INSTALL_ERROR;
     }
   } else if (should_wipe_ab) {
-    if (!wipe_ab_device(wipe_package_size)) {
+    if (!WipeAbDevice(device, wipe_package_size)) {
       status = INSTALL_ERROR;
     }
   } else if (sideload) {
@@ -989,7 +840,7 @@
   //    for 5s followed by an automatic reboot.
   if (status != INSTALL_REBOOT) {
     if (status == INSTALL_NONE || ui->IsTextVisible()) {
-      Device::BuiltinAction temp = prompt_and_wait(device, status);
+      auto temp = PromptAndWait(device, status);
       if (temp != Device::NO_ACTION) {
         next_action = temp;
       }
diff --git a/recovery_main.cpp b/recovery_main.cpp
index de8ac1f..7fbdf9a 100644
--- a/recovery_main.cpp
+++ b/recovery_main.cpp
@@ -41,8 +41,8 @@
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <bootloader_message/bootloader_message.h>
-#include <cutils/android_reboot.h>
 #include <cutils/sockets.h>
+#include <fs_mgr/roots.h>
 #include <private/android_logger.h> /* private pmsg functions */
 #include <selinux/android.h>
 #include <selinux/label.h>
@@ -375,7 +375,6 @@
     }
 
     if (locale.empty()) {
-      static constexpr const char* DEFAULT_LOCALE = "en-US";
       locale = DEFAULT_LOCALE;
     }
   }
@@ -472,27 +471,31 @@
     switch (ret) {
       case Device::SHUTDOWN:
         ui->Print("Shutting down...\n");
-        // TODO: Move all the reboots to reboot(), which should conditionally set quiescent flag.
-        android::base::SetProperty(ANDROID_RB_PROPERTY, "shutdown,");
+        Shutdown("userrequested,recovery");
+        break;
+
+      case Device::SHUTDOWN_FROM_FASTBOOT:
+        ui->Print("Shutting down...\n");
+        Shutdown("userrequested,fastboot");
         break;
 
       case Device::REBOOT_BOOTLOADER:
         ui->Print("Rebooting to bootloader...\n");
-        android::base::SetProperty(ANDROID_RB_PROPERTY, "reboot,bootloader");
+        Reboot("bootloader");
         break;
 
       case Device::REBOOT_FASTBOOT:
         ui->Print("Rebooting to recovery/fastboot...\n");
-        android::base::SetProperty(ANDROID_RB_PROPERTY, "reboot,fastboot");
+        Reboot("fastboot");
         break;
 
       case Device::REBOOT_RECOVERY:
         ui->Print("Rebooting to recovery...\n");
-        reboot("reboot,recovery");
+        Reboot("recovery");
         break;
 
       case Device::REBOOT_RESCUE: {
-        // Not using `reboot("reboot,rescue")`, as it requires matching support in kernel and/or
+        // Not using `Reboot("rescue")`, as it requires matching support in kernel and/or
         // bootloader.
         bootloader_message boot = {};
         strlcpy(boot.command, "boot-rescue", sizeof(boot.command));
@@ -503,14 +506,14 @@
           continue;
         }
         ui->Print("Rebooting to recovery/rescue...\n");
-        reboot("reboot,recovery");
+        Reboot("recovery");
         break;
       }
 
       case Device::ENTER_FASTBOOT:
-        if (logical_partitions_mapped()) {
+        if (android::fs_mgr::LogicalPartitionsMapped()) {
           ui->Print("Partitions may be mounted - rebooting to enter fastboot.");
-          android::base::SetProperty(ANDROID_RB_PROPERTY, "reboot,fastboot");
+          Reboot("fastboot");
         } else {
           LOG(INFO) << "Entering fastboot";
           fastboot = true;
@@ -522,9 +525,19 @@
         fastboot = false;
         break;
 
+      case Device::REBOOT:
+        ui->Print("Rebooting...\n");
+        Reboot("userrequested,recovery");
+        break;
+
+      case Device::REBOOT_FROM_FASTBOOT:
+        ui->Print("Rebooting...\n");
+        Reboot("userrequested,fastboot");
+        break;
+
       default:
         ui->Print("Rebooting...\n");
-        reboot("reboot,");
+        Reboot("unknown" + std::to_string(ret));
         break;
     }
   }
diff --git a/recovery_ui/include/recovery_ui/device.h b/recovery_ui/include/recovery_ui/device.h
index 7c76cdb..9a4edf2 100644
--- a/recovery_ui/include/recovery_ui/device.h
+++ b/recovery_ui/include/recovery_ui/device.h
@@ -58,6 +58,8 @@
     REBOOT_FASTBOOT = 17,
     REBOOT_RECOVERY = 18,
     REBOOT_RESCUE = 19,
+    REBOOT_FROM_FASTBOOT = 20,
+    SHUTDOWN_FROM_FASTBOOT = 21,
   };
 
   explicit Device(RecoveryUI* ui);
diff --git a/recovery_ui/include/recovery_ui/ui.h b/recovery_ui/include/recovery_ui/ui.h
index d55322c..797e2f0 100644
--- a/recovery_ui/include/recovery_ui/ui.h
+++ b/recovery_ui/include/recovery_ui/ui.h
@@ -27,6 +27,8 @@
 #include <thread>
 #include <vector>
 
+static constexpr const char* DEFAULT_LOCALE = "en-US";
+
 // Abstract class for controlling the user interface during recovery.
 class RecoveryUI {
  public:
diff --git a/recovery_ui/screen_ui.cpp b/recovery_ui/screen_ui.cpp
index 870db62..8230045 100644
--- a/recovery_ui/screen_ui.cpp
+++ b/recovery_ui/screen_ui.cpp
@@ -817,12 +817,22 @@
 
 std::unique_ptr<GRSurface> ScreenRecoveryUI::LoadLocalizedBitmap(const std::string& filename) {
   GRSurface* surface;
-  if (auto result = res_create_localized_alpha_surface(filename.c_str(), locale_.c_str(), &surface);
-      result < 0) {
-    LOG(ERROR) << "Failed to load bitmap " << filename << " (error " << result << ")";
-    return nullptr;
+  auto result = res_create_localized_alpha_surface(filename.c_str(), locale_.c_str(), &surface);
+  if (result == 0) {
+    return std::unique_ptr<GRSurface>(surface);
   }
-  return std::unique_ptr<GRSurface>(surface);
+  // TODO(xunchang) create a error code enum to refine the retry condition.
+  LOG(WARNING) << "Failed to load bitmap " << filename << " for locale " << locale_ << " (error "
+               << result << "). Falling back to use default locale.";
+
+  result = res_create_localized_alpha_surface(filename.c_str(), DEFAULT_LOCALE, &surface);
+  if (result == 0) {
+    return std::unique_ptr<GRSurface>(surface);
+  }
+
+  LOG(ERROR) << "Failed to load bitmap " << filename << " for locale " << DEFAULT_LOCALE
+             << " (error " << result << ")";
+  return nullptr;
 }
 
 static char** Alloc2d(size_t rows, size_t cols) {
diff --git a/recovery_ui/ui.cpp b/recovery_ui/ui.cpp
index b7107ff..78b014a 100644
--- a/recovery_ui/ui.cpp
+++ b/recovery_ui/ui.cpp
@@ -375,7 +375,7 @@
 
       case RecoveryUI::REBOOT:
         if (reboot_enabled) {
-          reboot("reboot,");
+          Reboot("userrequested,recovery,ui");
           while (true) {
             pause();
           }
diff --git a/tests/Android.bp b/tests/Android.bp
index 09ef716..4969c08 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -79,6 +79,8 @@
     "libinstall",
     "librecovery_ui",
     "libminui",
+    "libfusesideload",
+    "libbootloader_message",
     "libotautil",
 
     "libhealthhalutils",
@@ -87,10 +89,8 @@
 
     "android.hardware.health@2.0",
     "android.hardware.health@1.0",
-    "libbootloader_message",
     "libext4_utils",
     "libfs_mgr",
-    "libfusesideload",
     "libhidl-gen-utils",
     "libhidlbase",
     "libhidltransport",
@@ -107,6 +107,8 @@
 
     defaults: [
         "recovery_test_defaults",
+        "libupdater_defaults",
+        "libupdater_device_defaults",
     ],
 
     test_suites: ["device-tests"],
@@ -115,16 +117,23 @@
         "unit/*.cpp",
     ],
 
-    static_libs: libapplypatch_static_libs + [
-        "libinstall",
+    static_libs: libapplypatch_static_libs + librecovery_static_libs + [
         "librecovery_ui",
+        "libfusesideload",
         "libminui",
         "libotautil",
-        "libupdater",
+        "libupdater_device",
+        "libupdater_core",
+        "libupdate_verifier",
+
         "libgtest_prod",
+        "libprotobuf-cpp-lite",
     ],
 
-    data: ["testdata/*"],
+    data: [
+        "testdata/*",
+        ":res-testdata",
+    ],
 }
 
 cc_test {
@@ -142,33 +151,6 @@
     ],
 }
 
-cc_test {
-    name: "recovery_component_test",
-    isolated: true,
-
-    defaults: [
-        "recovery_test_defaults",
-        "libupdater_defaults",
-    ],
-
-    test_suites: ["device-tests"],
-
-    srcs: [
-        "component/*.cpp",
-    ],
-
-    static_libs: libapplypatch_static_libs + librecovery_static_libs + [
-        "libupdater",
-        "libupdate_verifier",
-        "libprotobuf-cpp-lite",
-    ],
-
-    data: [
-        "testdata/*",
-        ":res-testdata",
-    ],
-}
-
 cc_test_host {
     name: "recovery_host_test",
     isolated: true,
@@ -178,7 +160,7 @@
     ],
 
     srcs: [
-        "component/imgdiff_test.cpp",
+        "unit/imgdiff_test.cpp",
     ],
 
     static_libs: [
@@ -197,6 +179,8 @@
         "libz",
     ],
 
+    test_suites: ["general-tests"],
+
     data: ["testdata/*"],
 
     target: {
diff --git a/tests/AndroidTest.xml b/tests/AndroidTest.xml
deleted file mode 100644
index 6b86085..0000000
--- a/tests/AndroidTest.xml
+++ /dev/null
@@ -1,33 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2017 The Android Open Source Project
-
-     Licensed under the Apache License, Version 2.0 (the "License");
-     you may not use this file except in compliance with the License.
-     You may obtain a copy of the License at
-
-          http://www.apache.org/licenses/LICENSE-2.0
-
-     Unless required by applicable law or agreed to in writing, software
-     distributed under the License is distributed on an "AS IS" BASIS,
-     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-     See the License for the specific language governing permissions and
-     limitations under the License.
--->
-<configuration description="Config for recovery_component_test and recovery_unit_test">
-    <target_preparer class="com.android.tradefed.targetprep.PushFilePreparer">
-        <option name="cleanup" value="true" />
-        <option name="push" value="recovery_component_test->/data/local/tmp/recovery_component_test/recovery_component_test" />
-        <option name="push" value="testdata->/data/local/tmp/recovery_component_test/testdata" />
-        <option name="push" value="recovery_unit_test->/data/local/tmp/recovery_unit_test/recovery_unit_test" />
-        <option name="push" value="testdata->/data/local/tmp/recovery_unit_test/testdata" />
-    </target_preparer>
-    <option name="test-suite-tag" value="apct" />
-    <test class="com.android.tradefed.testtype.GTest" >
-        <option name="native-test-device-path" value="/data/local/tmp/recovery_component_test" />
-        <option name="module-name" value="recovery_component_test" />
-    </test>
-    <test class="com.android.tradefed.testtype.GTest" >
-        <option name="native-test-device-path" value="/data/local/tmp/recovery_unit_test" />
-        <option name="module-name" value="recovery_unit_test" />
-    </test>
-</configuration>
diff --git a/tests/component/resources_test.cpp b/tests/component/resources_test.cpp
deleted file mode 100644
index d7fdb8f..0000000
--- a/tests/component/resources_test.cpp
+++ /dev/null
@@ -1,120 +0,0 @@
-/*
- * Copyright (C) 2018 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <dirent.h>
-#include <stdio.h>
-#include <stdlib.h>
-
-#include <memory>
-#include <string>
-#include <vector>
-
-#include <android-base/file.h>
-#include <android-base/strings.h>
-#include <gtest/gtest.h>
-#include <png.h>
-
-#include "minui/minui.h"
-#include "private/resources.h"
-
-static const std::string kLocale = "zu";
-
-static const std::vector<std::string> kResourceImagesDirs{
-  "res-mdpi/images/",   "res-hdpi/images/",    "res-xhdpi/images/",
-  "res-xxhdpi/images/", "res-xxxhdpi/images/",
-};
-
-static int png_filter(const dirent* de) {
-  if (de->d_type != DT_REG || !android::base::EndsWith(de->d_name, "_text.png")) {
-    return 0;
-  }
-  return 1;
-}
-
-// Finds out all the PNG files to test, which stay under the same dir with the executabl..
-static std::vector<std::string> add_files() {
-  std::vector<std::string> files;
-  for (const std::string& images_dir : kResourceImagesDirs) {
-    static std::string exec_dir = android::base::GetExecutableDirectory();
-    std::string dir_path = exec_dir + "/" + images_dir;
-    dirent** namelist;
-    int n = scandir(dir_path.c_str(), &namelist, png_filter, alphasort);
-    if (n == -1) {
-      printf("Failed to scandir %s: %s\n", dir_path.c_str(), strerror(errno));
-      continue;
-    }
-    if (n == 0) {
-      printf("No file is added for test in %s\n", dir_path.c_str());
-    }
-
-    while (n--) {
-      std::string file_path = dir_path + namelist[n]->d_name;
-      files.push_back(file_path);
-      free(namelist[n]);
-    }
-    free(namelist);
-  }
-  return files;
-}
-
-class ResourcesTest : public testing::TestWithParam<std::string> {
- public:
-  static std::vector<std::string> png_list;
-
- protected:
-  void SetUp() override {
-    png_ = std::make_unique<PngHandler>(GetParam());
-    ASSERT_TRUE(png_);
-
-    ASSERT_EQ(PNG_COLOR_TYPE_GRAY, png_->color_type()) << "Recovery expects grayscale PNG file.";
-    ASSERT_LT(static_cast<png_uint_32>(5), png_->width());
-    ASSERT_LT(static_cast<png_uint_32>(0), png_->height());
-    ASSERT_EQ(1, png_->channels()) << "Recovery background text images expects 1-channel PNG file.";
-  }
-
-  std::unique_ptr<PngHandler> png_{ nullptr };
-};
-
-// Parses a png file and tests if it's qualified for the background text image under recovery.
-TEST_P(ResourcesTest, ValidateLocale) {
-  std::vector<unsigned char> row(png_->width());
-  for (png_uint_32 y = 0; y < png_->height(); ++y) {
-    png_read_row(png_->png_ptr(), row.data(), nullptr);
-    int w = (row[1] << 8) | row[0];
-    int h = (row[3] << 8) | row[2];
-    int len = row[4];
-    EXPECT_LT(0, w);
-    EXPECT_LT(0, h);
-    EXPECT_LT(0, len) << "Locale string should be non-empty.";
-    EXPECT_NE(0, row[5]) << "Locale string is missing.";
-
-    ASSERT_GE(png_->height(), y + 1 + h) << "Locale: " << kLocale << " is not found in the file.";
-    char* loc = reinterpret_cast<char*>(&row[5]);
-    if (matches_locale(loc, kLocale.c_str())) {
-      EXPECT_TRUE(android::base::StartsWith(loc, kLocale));
-      break;
-    }
-    for (int i = 0; i < h; ++i, ++y) {
-      png_read_row(png_->png_ptr(), row.data(), nullptr);
-    }
-  }
-}
-
-std::vector<std::string> ResourcesTest::png_list = add_files();
-
-INSTANTIATE_TEST_CASE_P(BackgroundTextValidation, ResourcesTest,
-                        ::testing::ValuesIn(ResourcesTest::png_list.cbegin(),
-                                            ResourcesTest::png_list.cend()));
diff --git a/tests/component/applypatch_modes_test.cpp b/tests/unit/applypatch_modes_test.cpp
similarity index 100%
rename from tests/component/applypatch_modes_test.cpp
rename to tests/unit/applypatch_modes_test.cpp
diff --git a/tests/component/bootloader_message_test.cpp b/tests/unit/bootloader_message_test.cpp
similarity index 100%
rename from tests/component/bootloader_message_test.cpp
rename to tests/unit/bootloader_message_test.cpp
diff --git a/tests/component/edify_test.cpp b/tests/unit/edify_test.cpp
similarity index 100%
rename from tests/component/edify_test.cpp
rename to tests/unit/edify_test.cpp
diff --git a/tests/unit/fuse_provider_test.cpp b/tests/unit/fuse_provider_test.cpp
new file mode 100644
index 0000000..c5995dd
--- /dev/null
+++ b/tests/unit/fuse_provider_test.cpp
@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include <functional>
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <gtest/gtest.h>
+
+#include "fuse_provider.h"
+#include "fuse_sideload.h"
+#include "install/install.h"
+
+TEST(FuseBlockMapTest, CreateFromBlockMap_smoke) {
+  TemporaryFile fake_block_device;
+  std::vector<std::string> lines = {
+    fake_block_device.path, "10000 4096", "3", "10 11", "20 21", "22 23",
+  };
+
+  TemporaryFile temp_file;
+  android::base::WriteStringToFile(android::base::Join(lines, '\n'), temp_file.path);
+  auto block_map_data = FuseBlockDataProvider::CreateFromBlockMap(temp_file.path, 4096);
+
+  ASSERT_TRUE(block_map_data);
+  ASSERT_EQ(10000, block_map_data->file_size());
+  ASSERT_EQ(4096, block_map_data->fuse_block_size());
+  ASSERT_EQ(RangeSet({ { 10, 11 }, { 20, 21 }, { 22, 23 } }), block_map_data->ranges());
+}
+
+TEST(FuseBlockMapTest, ReadBlockAlignedData_smoke) {
+  std::string content;
+  content.reserve(40960);
+  for (char c = 0; c < 10; c++) {
+    content += std::string(4096, c);
+  }
+  TemporaryFile fake_block_device;
+  ASSERT_TRUE(android::base::WriteStringToFile(content, fake_block_device.path));
+
+  std::vector<std::string> lines = {
+    fake_block_device.path,
+    "20000 4096",
+    "1",
+    "0 5",
+  };
+  TemporaryFile temp_file;
+  android::base::WriteStringToFile(android::base::Join(lines, '\n'), temp_file.path);
+  auto block_map_data = FuseBlockDataProvider::CreateFromBlockMap(temp_file.path, 4096);
+
+  std::vector<uint8_t> result(2000);
+  ASSERT_TRUE(block_map_data->ReadBlockAlignedData(result.data(), 2000, 1));
+  ASSERT_EQ(std::vector<uint8_t>(content.begin() + 4096, content.begin() + 6096), result);
+
+  result.resize(20000);
+  ASSERT_TRUE(block_map_data->ReadBlockAlignedData(result.data(), 20000, 0));
+  ASSERT_EQ(std::vector<uint8_t>(content.begin(), content.begin() + 20000), result);
+}
+
+TEST(FuseBlockMapTest, ReadBlockAlignedData_large_fuse_block) {
+  std::string content;
+  for (char c = 0; c < 10; c++) {
+    content += std::string(4096, c);
+  }
+
+  TemporaryFile temp_file;
+  ASSERT_TRUE(android::base::WriteStringToFile(content, temp_file.path));
+
+  std::vector<std::string> lines = {
+    temp_file.path, "36384 4096", "2", "0 5", "6 10",
+  };
+  TemporaryFile block_map;
+  ASSERT_TRUE(android::base::WriteStringToFile(android::base::Join(lines, '\n'), block_map.path));
+
+  auto block_map_data = FuseBlockDataProvider::CreateFromBlockMap(block_map.path, 16384);
+  ASSERT_TRUE(block_map_data);
+
+  std::vector<uint8_t> result(20000);
+  // Out of bound read
+  ASSERT_FALSE(block_map_data->ReadBlockAlignedData(result.data(), 20000, 2));
+  ASSERT_TRUE(block_map_data->ReadBlockAlignedData(result.data(), 20000, 1));
+  // expected source block contains: 4, 6-9
+  std::string expected = content.substr(16384, 4096) + content.substr(24576, 15904);
+  ASSERT_EQ(std::vector<uint8_t>(expected.begin(), expected.end()), result);
+}
diff --git a/tests/component/sideload_test.cpp b/tests/unit/fuse_sideload_test.cpp
similarity index 100%
rename from tests/component/sideload_test.cpp
rename to tests/unit/fuse_sideload_test.cpp
diff --git a/tests/component/imgdiff_test.cpp b/tests/unit/imgdiff_test.cpp
similarity index 100%
rename from tests/component/imgdiff_test.cpp
rename to tests/unit/imgdiff_test.cpp
diff --git a/tests/component/install_test.cpp b/tests/unit/install_test.cpp
similarity index 90%
rename from tests/component/install_test.cpp
rename to tests/unit/install_test.cpp
index 3851329..4ec4099 100644
--- a/tests/component/install_test.cpp
+++ b/tests/unit/install_test.cpp
@@ -33,6 +33,7 @@
 #include <ziparchive/zip_writer.h>
 
 #include "install/install.h"
+#include "install/wipe_device.h"
 #include "otautil/paths.h"
 #include "private/setup_commands.h"
 
@@ -204,7 +205,7 @@
   std::string binary_path = std::string(td.path) + "/update_binary";
   Paths::Get().set_temporary_update_binary(binary_path);
   std::vector<std::string> cmd;
-  ASSERT_EQ(0, SetUpNonAbUpdateCommands(package, zip, 0, status_fd, &cmd));
+  ASSERT_TRUE(SetUpNonAbUpdateCommands(package, zip, 0, status_fd, &cmd));
   ASSERT_EQ(4U, cmd.size());
   ASSERT_EQ(binary_path, cmd[0]);
   ASSERT_EQ("3", cmd[1]);  // RECOVERY_API_VERSION
@@ -216,7 +217,7 @@
 
   // With non-zero retry count. update_binary will be removed automatically.
   cmd.clear();
-  ASSERT_EQ(0, SetUpNonAbUpdateCommands(package, zip, 2, status_fd, &cmd));
+  ASSERT_TRUE(SetUpNonAbUpdateCommands(package, zip, 2, status_fd, &cmd));
   ASSERT_EQ(5U, cmd.size());
   ASSERT_EQ(binary_path, cmd[0]);
   ASSERT_EQ("3", cmd[1]);  // RECOVERY_API_VERSION
@@ -243,7 +244,7 @@
   TemporaryDir td;
   Paths::Get().set_temporary_update_binary(std::string(td.path) + "/update_binary");
   std::vector<std::string> cmd;
-  ASSERT_EQ(INSTALL_CORRUPT, SetUpNonAbUpdateCommands(package, zip, 0, status_fd, &cmd));
+  ASSERT_FALSE(SetUpNonAbUpdateCommands(package, zip, 0, status_fd, &cmd));
   CloseArchive(zip);
 }
 
@@ -270,19 +271,18 @@
 
   ZipArchiveHandle zip;
   ASSERT_EQ(0, OpenArchive(temp_file.path, &zip));
-  ZipString payload_name("payload.bin");
   ZipEntry payload_entry;
-  ASSERT_EQ(0, FindEntry(zip, payload_name, &payload_entry));
+  ASSERT_EQ(0, FindEntry(zip, "payload.bin", &payload_entry));
 
   std::map<std::string, std::string> metadata;
   ASSERT_TRUE(ReadMetadataFromPackage(zip, &metadata));
   if (success) {
-    ASSERT_EQ(0, CheckPackageMetadata(metadata, OtaType::AB));
+    ASSERT_TRUE(CheckPackageMetadata(metadata, OtaType::AB));
 
     int status_fd = 10;
     std::string package = "/path/to/update.zip";
     std::vector<std::string> cmd;
-    ASSERT_EQ(0, SetUpAbUpdateCommands(package, zip, status_fd, &cmd));
+    ASSERT_TRUE(SetUpAbUpdateCommands(package, zip, status_fd, &cmd));
     ASSERT_EQ(5U, cmd.size());
     ASSERT_EQ("/system/bin/update_engine_sideload", cmd[0]);
     ASSERT_EQ("--payload=file://" + package, cmd[1]);
@@ -290,7 +290,7 @@
     ASSERT_EQ("--headers=" + properties, cmd[3]);
     ASSERT_EQ("--status_fd=" + std::to_string(status_fd), cmd[4]);
   } else {
-    ASSERT_EQ(INSTALL_ERROR, CheckPackageMetadata(metadata, OtaType::AB));
+    ASSERT_FALSE(CheckPackageMetadata(metadata, OtaType::AB));
   }
   CloseArchive(zip);
 }
@@ -325,7 +325,7 @@
   int status_fd = 10;
   std::string package = "/path/to/update.zip";
   std::vector<std::string> cmd;
-  ASSERT_EQ(INSTALL_CORRUPT, SetUpAbUpdateCommands(package, zip, status_fd, &cmd));
+  ASSERT_FALSE(SetUpAbUpdateCommands(package, zip, status_fd, &cmd));
   CloseArchive(zip);
 }
 
@@ -358,8 +358,8 @@
   VerifyAbUpdateCommands(long_serialno);
 }
 
-static void test_check_package_metadata(const std::string& metadata_string, OtaType ota_type,
-                                        int exptected_result) {
+static void TestCheckPackageMetadata(const std::string& metadata_string, OtaType ota_type,
+                                     bool exptected_result) {
   TemporaryFile temp_file;
   BuildZipArchive(
       {
@@ -387,7 +387,7 @@
           "post-timestamp=" + std::to_string(std::numeric_limits<int64_t>::max()),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::AB, false);
 
   // Checks if ota-type matches
   metadata = android::base::Join(
@@ -397,9 +397,9 @@
           "post-timestamp=" + std::to_string(std::numeric_limits<int64_t>::max()),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, 0);
+  TestCheckPackageMetadata(metadata, OtaType::AB, true);
 
-  test_check_package_metadata(metadata, OtaType::BRICK, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, false);
 }
 
 TEST(InstallTest, CheckPackageMetadata_device_type) {
@@ -409,7 +409,7 @@
           "ota-type=BRICK",
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::BRICK, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, false);
 
   // device type mismatches
   metadata = android::base::Join(
@@ -418,7 +418,7 @@
           "pre-device=dummy_device_type",
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::BRICK, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, false);
 }
 
 TEST(InstallTest, CheckPackageMetadata_serial_number_smoke) {
@@ -432,7 +432,7 @@
           "pre-device=" + device,
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::BRICK, 0);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, true);
 
   // Serial number mismatches
   metadata = android::base::Join(
@@ -442,7 +442,7 @@
           "serialno=dummy_serial",
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::BRICK, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, false);
 
   std::string serialno = android::base::GetProperty("ro.serialno", "");
   ASSERT_NE("", serialno);
@@ -453,7 +453,7 @@
           "serialno=" + serialno,
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::BRICK, 0);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, true);
 }
 
 TEST(InstallTest, CheckPackageMetadata_multiple_serial_number) {
@@ -477,7 +477,7 @@
           "serialno=" + android::base::Join(serial_numbers, '|'),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::BRICK, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, false);
 
   serial_numbers.emplace_back(serialno);
   std::shuffle(serial_numbers.begin(), serial_numbers.end(), std::default_random_engine());
@@ -488,7 +488,7 @@
           "serialno=" + android::base::Join(serial_numbers, '|'),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::BRICK, 0);
+  TestCheckPackageMetadata(metadata, OtaType::BRICK, true);
 }
 
 TEST(InstallTest, CheckPackageMetadata_ab_build_version) {
@@ -506,7 +506,7 @@
           "post-timestamp=" + std::to_string(std::numeric_limits<int64_t>::max()),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, 0);
+  TestCheckPackageMetadata(metadata, OtaType::AB, true);
 
   metadata = android::base::Join(
       std::vector<std::string>{
@@ -516,7 +516,7 @@
           "post-timestamp=" + std::to_string(std::numeric_limits<int64_t>::max()),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::AB, false);
 }
 
 TEST(InstallTest, CheckPackageMetadata_ab_fingerprint) {
@@ -534,7 +534,7 @@
           "post-timestamp=" + std::to_string(std::numeric_limits<int64_t>::max()),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, 0);
+  TestCheckPackageMetadata(metadata, OtaType::AB, true);
 
   metadata = android::base::Join(
       std::vector<std::string>{
@@ -544,7 +544,7 @@
           "post-timestamp=" + std::to_string(std::numeric_limits<int64_t>::max()),
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::AB, false);
 }
 
 TEST(InstallTest, CheckPackageMetadata_ab_post_timestamp) {
@@ -558,7 +558,7 @@
           "pre-device=" + device,
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::AB, false);
 
   // post timestamp should be larger than the timestamp on device.
   metadata = android::base::Join(
@@ -568,7 +568,7 @@
           "post-timestamp=0",
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::AB, false);
 
   // fingerprint is required for downgrade
   metadata = android::base::Join(
@@ -579,7 +579,7 @@
           "ota-downgrade=yes",
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, INSTALL_ERROR);
+  TestCheckPackageMetadata(metadata, OtaType::AB, false);
 
   std::string finger_print = android::base::GetProperty("ro.build.fingerprint", "");
   ASSERT_NE("", finger_print);
@@ -593,5 +593,5 @@
           "ota-downgrade=yes",
       },
       "\n");
-  test_check_package_metadata(metadata, OtaType::AB, 0);
+  TestCheckPackageMetadata(metadata, OtaType::AB, true);
 }
diff --git a/tests/unit/locale_test.cpp b/tests/unit/locale_test.cpp
index cdaba0e..c69434c 100644
--- a/tests/unit/locale_test.cpp
+++ b/tests/unit/locale_test.cpp
@@ -27,7 +27,7 @@
   EXPECT_FALSE(matches_locale("en-GB", "en"));
   EXPECT_FALSE(matches_locale("en-GB", "en-US"));
   EXPECT_FALSE(matches_locale("en-US", ""));
-  // Empty locale prefix in the PNG file will match the input locale.
-  EXPECT_TRUE(matches_locale("", "en-US"));
+  // Empty locale prefix in the PNG file should not match the input locale.
+  EXPECT_FALSE(matches_locale("", "en-US"));
   EXPECT_TRUE(matches_locale("sr-Latn", "sr-Latn-BA"));
 }
diff --git a/tests/unit/package_test.cpp b/tests/unit/package_test.cpp
index a735a69..5e31f7f 100644
--- a/tests/unit/package_test.cpp
+++ b/tests/unit/package_test.cpp
@@ -105,10 +105,9 @@
     ASSERT_TRUE(zip);
 
     // Check that we can extract one zip entry.
-    std::string entry_name = "dir1/file3.txt";
-    ZipString path(entry_name.c_str());
+    std::string_view entry_name = "dir1/file3.txt";
     ZipEntry entry;
-    ASSERT_EQ(0, FindEntry(zip, path, &entry));
+    ASSERT_EQ(0, FindEntry(zip, entry_name, &entry));
 
     std::vector<uint8_t> extracted(entry_name.size());
     ASSERT_EQ(0, ExtractToMemory(zip, &entry, extracted.data(), extracted.size()));
diff --git a/tests/unit/rangeset_test.cpp b/tests/unit/rangeset_test.cpp
index fc72f2f..699f933 100644
--- a/tests/unit/rangeset_test.cpp
+++ b/tests/unit/rangeset_test.cpp
@@ -18,6 +18,7 @@
 #include <sys/types.h>
 
 #include <limits>
+#include <optional>
 #include <vector>
 
 #include <gtest/gtest.h>
@@ -248,6 +249,29 @@
   ASSERT_EQ("6,1,3,4,6,15,22", RangeSet::Parse("6,1,3,4,6,15,22").ToString());
 }
 
+TEST(RangeSetTest, GetSubRanges_invalid) {
+  RangeSet range0({ { 1, 11 }, { 20, 30 } });
+  ASSERT_FALSE(range0.GetSubRanges(0, 21));  // too many blocks
+  ASSERT_FALSE(range0.GetSubRanges(21, 1));  // start block OOB
+}
+
+TEST(RangeSetTest, GetSubRanges_empty) {
+  RangeSet range0({ { 1, 11 }, { 20, 30 } });
+  ASSERT_EQ(RangeSet{}, range0.GetSubRanges(1, 0));  // empty num_of_blocks
+}
+
+TEST(RangeSetTest, GetSubRanges_smoke) {
+  RangeSet range0({ { 10, 11 } });
+  ASSERT_EQ(RangeSet({ { 10, 11 } }), range0.GetSubRanges(0, 1));
+
+  RangeSet range1({ { 10, 11 }, { 20, 21 }, { 30, 31 } });
+  ASSERT_EQ(range1, range1.GetSubRanges(0, 3));
+  ASSERT_EQ(RangeSet({ { 20, 21 } }), range1.GetSubRanges(1, 1));
+
+  RangeSet range2({ { 1, 11 }, { 20, 25 }, { 30, 35 } });
+  ASSERT_EQ(RangeSet({ { 10, 11 }, { 20, 25 }, { 30, 31 } }), range2.GetSubRanges(9, 7));
+}
+
 TEST(SortedRangeSetTest, Insert) {
   SortedRangeSet rs({ { 2, 3 }, { 4, 6 }, { 8, 14 } });
   rs.Insert({ 1, 2 });
diff --git a/tests/unit/resources_test.cpp b/tests/unit/resources_test.cpp
index c3f7271..3027443 100644
--- a/tests/unit/resources_test.cpp
+++ b/tests/unit/resources_test.cpp
@@ -14,12 +14,62 @@
  * limitations under the License.
  */
 
-#include <string>
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
 
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/strings.h>
 #include <gtest/gtest.h>
+#include <png.h>
 
 #include "common/test_constants.h"
 #include "minui/minui.h"
+#include "private/resources.h"
+
+static const std::string kLocale = "zu";
+
+static const std::vector<std::string> kResourceImagesDirs{
+  "res-mdpi/images/",   "res-hdpi/images/",    "res-xhdpi/images/",
+  "res-xxhdpi/images/", "res-xxxhdpi/images/",
+};
+
+static int png_filter(const dirent* de) {
+  if (de->d_type != DT_REG || !android::base::EndsWith(de->d_name, "_text.png")) {
+    return 0;
+  }
+  return 1;
+}
+
+// Finds out all the PNG files to test, which stay under the same dir with the executabl..
+static std::vector<std::string> add_files() {
+  std::vector<std::string> files;
+  for (const std::string& images_dir : kResourceImagesDirs) {
+    static std::string exec_dir = android::base::GetExecutableDirectory();
+    std::string dir_path = exec_dir + "/" + images_dir;
+    dirent** namelist;
+    int n = scandir(dir_path.c_str(), &namelist, png_filter, alphasort);
+    if (n == -1) {
+      printf("Failed to scandir %s: %s\n", dir_path.c_str(), strerror(errno));
+      continue;
+    }
+    if (n == 0) {
+      printf("No file is added for test in %s\n", dir_path.c_str());
+    }
+
+    while (n--) {
+      std::string file_path = dir_path + namelist[n]->d_name;
+      files.push_back(file_path);
+      free(namelist[n]);
+    }
+    free(namelist);
+  }
+  return files;
+}
 
 TEST(ResourcesTest, res_create_multi_display_surface) {
   GRSurface** frames;
@@ -35,3 +85,52 @@
   }
   free(frames);
 }
+
+class ResourcesTest : public testing::TestWithParam<std::string> {
+ public:
+  static std::vector<std::string> png_list;
+
+ protected:
+  void SetUp() override {
+    png_ = std::make_unique<PngHandler>(GetParam());
+    ASSERT_TRUE(png_);
+
+    ASSERT_EQ(PNG_COLOR_TYPE_GRAY, png_->color_type()) << "Recovery expects grayscale PNG file.";
+    ASSERT_LT(static_cast<png_uint_32>(5), png_->width());
+    ASSERT_LT(static_cast<png_uint_32>(0), png_->height());
+    ASSERT_EQ(1, png_->channels()) << "Recovery background text images expects 1-channel PNG file.";
+  }
+
+  std::unique_ptr<PngHandler> png_{ nullptr };
+};
+
+// Parses a png file and tests if it's qualified for the background text image under recovery.
+TEST_P(ResourcesTest, ValidateLocale) {
+  std::vector<unsigned char> row(png_->width());
+  for (png_uint_32 y = 0; y < png_->height(); ++y) {
+    png_read_row(png_->png_ptr(), row.data(), nullptr);
+    int w = (row[1] << 8) | row[0];
+    int h = (row[3] << 8) | row[2];
+    int len = row[4];
+    EXPECT_LT(0, w);
+    EXPECT_LT(0, h);
+    EXPECT_LT(0, len) << "Locale string should be non-empty.";
+    EXPECT_NE(0, row[5]) << "Locale string is missing.";
+
+    ASSERT_GE(png_->height(), y + 1 + h) << "Locale: " << kLocale << " is not found in the file.";
+    char* loc = reinterpret_cast<char*>(&row[5]);
+    if (matches_locale(loc, kLocale.c_str())) {
+      EXPECT_TRUE(android::base::StartsWith(loc, kLocale));
+      break;
+    }
+    for (int i = 0; i < h; ++i, ++y) {
+      png_read_row(png_->png_ptr(), row.data(), nullptr);
+    }
+  }
+}
+
+std::vector<std::string> ResourcesTest::png_list = add_files();
+
+INSTANTIATE_TEST_CASE_P(BackgroundTextValidation, ResourcesTest,
+                        ::testing::ValuesIn(ResourcesTest::png_list.cbegin(),
+                                            ResourcesTest::png_list.cend()));
diff --git a/tests/unit/sysutil_test.cpp b/tests/unit/sysutil_test.cpp
index 3466e8e..64b8956 100644
--- a/tests/unit/sysutil_test.cpp
+++ b/tests/unit/sysutil_test.cpp
@@ -67,7 +67,7 @@
     "/dev/abc",
     "42949672950 4294967295",
     "1",
-    "0 9",
+    "0 10",
   };
 
   TemporaryFile temp_file;
diff --git a/tests/component/uncrypt_test.cpp b/tests/unit/uncrypt_test.cpp
similarity index 100%
rename from tests/component/uncrypt_test.cpp
rename to tests/unit/uncrypt_test.cpp
diff --git a/tests/component/update_verifier_test.cpp b/tests/unit/update_verifier_test.cpp
similarity index 100%
rename from tests/component/update_verifier_test.cpp
rename to tests/unit/update_verifier_test.cpp
diff --git a/tests/component/updater_test.cpp b/tests/unit/updater_test.cpp
similarity index 92%
rename from tests/component/updater_test.cpp
rename to tests/unit/updater_test.cpp
index a0a7b66..8993dd8 100644
--- a/tests/component/updater_test.cpp
+++ b/tests/unit/updater_test.cpp
@@ -52,21 +52,20 @@
 #include "updater/blockimg.h"
 #include "updater/install.h"
 #include "updater/updater.h"
+#include "updater/updater_runtime.h"
 
 using namespace std::string_literals;
 
 using PackageEntries = std::unordered_map<std::string, std::string>;
 
-struct selabel_handle* sehandle = nullptr;
-
 static void expect(const char* expected, const std::string& expr_str, CauseCode cause_code,
-                   UpdaterInfo* info = nullptr) {
+                   Updater* updater) {
   std::unique_ptr<Expr> e;
   int error_count = 0;
   ASSERT_EQ(0, ParseString(expr_str, &e, &error_count));
   ASSERT_EQ(0, error_count);
 
-  State state(expr_str, info);
+  State state(expr_str, updater);
 
   std::string result;
   bool status = Evaluate(&state, e, &result);
@@ -85,6 +84,11 @@
   ASSERT_EQ(cause_code, state.cause_code);
 }
 
+static void expect(const char* expected, const std::string& expr_str, CauseCode cause_code) {
+  Updater updater(std::make_unique<UpdaterRuntime>(nullptr));
+  expect(expected, expr_str, cause_code, &updater);
+}
+
 static void BuildUpdatePackage(const PackageEntries& entries, int fd) {
   FILE* zip_file_ptr = fdopen(fd, "wb");
   ZipWriter zip_writer(zip_file_ptr);
@@ -102,38 +106,6 @@
   ASSERT_EQ(0, fclose(zip_file_ptr));
 }
 
-static void RunBlockImageUpdate(bool is_verify, const PackageEntries& entries,
-                                const std::string& image_file, const std::string& result,
-                                CauseCode cause_code = kNoCause) {
-  CHECK(entries.find("transfer_list") != entries.end());
-
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
-
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
-
-  // Set up the handler, command_pipe, patch offset & length.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
-  TemporaryFile temp_pipe;
-  updater_info.cmd_pipe = fdopen(temp_pipe.release(), "wbe");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  std::string new_data = entries.find("new_data.br") != entries.end() ? "new_data.br" : "new_data";
-  std::string script = is_verify ? "block_image_verify" : "block_image_update";
-  script += R"((")" + image_file + R"(", package_extract_file("transfer_list"), ")" + new_data +
-            R"(", "patch_data"))";
-  expect(result.c_str(), script, cause_code, &updater_info);
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
-}
-
 static std::string GetSha1(std::string_view content) {
   uint8_t digest[SHA_DIGEST_LENGTH];
   SHA1(reinterpret_cast<const uint8_t*>(content.data()), content.size(), digest);
@@ -159,29 +131,26 @@
   return args[0].release();
 }
 
-class UpdaterTest : public ::testing::Test {
+class UpdaterTestBase {
  protected:
-  void SetUp() override {
+  UpdaterTestBase() : updater_(std::make_unique<UpdaterRuntime>(nullptr)) {}
+
+  void SetUp() {
     RegisterBuiltins();
     RegisterInstallFunctions();
     RegisterBlockImageFunctions();
 
-    RegisterFunction("blob_to_string", BlobToString);
-
     // Each test is run in a separate process (isolated mode). Shared temporary files won't cause
     // conflicts.
     Paths::Get().set_cache_temp_source(temp_saved_source_.path);
     Paths::Get().set_last_command_file(temp_last_command_.path);
     Paths::Get().set_stash_directory_base(temp_stash_base_.path);
 
-    // Enable a special command "abort" to simulate interruption.
-    Command::abort_allowed_ = true;
-
     last_command_file_ = temp_last_command_.path;
     image_file_ = image_temp_file_.path;
   }
 
-  void TearDown() override {
+  void TearDown() {
     // Clean up the last_command_file if any.
     ASSERT_TRUE(android::base::RemoveFileIfExists(last_command_file_));
 
@@ -191,16 +160,80 @@
     ASSERT_TRUE(android::base::RemoveFileIfExists(updated_marker));
   }
 
+  void RunBlockImageUpdate(bool is_verify, PackageEntries entries, const std::string& image_file,
+                           const std::string& result, CauseCode cause_code = kNoCause) {
+    CHECK(entries.find("transfer_list") != entries.end());
+    std::string new_data =
+        entries.find("new_data.br") != entries.end() ? "new_data.br" : "new_data";
+    std::string script = is_verify ? "block_image_verify" : "block_image_update";
+    script += R"((")" + image_file + R"(", package_extract_file("transfer_list"), ")" + new_data +
+              R"(", "patch_data"))";
+    entries.emplace(Updater::SCRIPT_NAME, script);
+
+    // Build the update package.
+    TemporaryFile zip_file;
+    BuildUpdatePackage(entries, zip_file.release());
+
+    // Set up the handler, command_pipe, patch offset & length.
+    TemporaryFile temp_pipe;
+    ASSERT_TRUE(updater_.Init(temp_pipe.release(), zip_file.path, false));
+    ASSERT_TRUE(updater_.RunUpdate());
+    ASSERT_EQ(result, updater_.GetResult());
+
+    // Parse the cause code written to the command pipe.
+    int received_cause_code = kNoCause;
+    std::string pipe_content;
+    ASSERT_TRUE(android::base::ReadFileToString(temp_pipe.path, &pipe_content));
+    auto lines = android::base::Split(pipe_content, "\n");
+    for (std::string_view line : lines) {
+      if (android::base::ConsumePrefix(&line, "log cause: ")) {
+        ASSERT_TRUE(android::base::ParseInt(line.data(), &received_cause_code));
+      }
+    }
+    ASSERT_EQ(cause_code, received_cause_code);
+  }
+
   TemporaryFile temp_saved_source_;
   TemporaryDir temp_stash_base_;
   std::string last_command_file_;
   std::string image_file_;
 
+  Updater updater_;
+
  private:
   TemporaryFile temp_last_command_;
   TemporaryFile image_temp_file_;
 };
 
+class UpdaterTest : public UpdaterTestBase, public ::testing::Test {
+ protected:
+  void SetUp() override {
+    UpdaterTestBase::SetUp();
+
+    RegisterFunction("blob_to_string", BlobToString);
+    // Enable a special command "abort" to simulate interruption.
+    Command::abort_allowed_ = true;
+  }
+
+  void TearDown() override {
+    UpdaterTestBase::TearDown();
+  }
+
+  void SetUpdaterCmdPipe(int fd) {
+    FILE* cmd_pipe = fdopen(fd, "w");
+    ASSERT_NE(nullptr, cmd_pipe);
+    updater_.cmd_pipe_.reset(cmd_pipe);
+  }
+
+  void SetUpdaterOtaPackageHandle(ZipArchiveHandle handle) {
+    updater_.package_handle_ = handle;
+  }
+
+  void FlushUpdaterCommandPipe() const {
+    fflush(updater_.cmd_pipe_.get());
+  }
+};
+
 TEST_F(UpdaterTest, getprop) {
     expect(android::base::GetProperty("ro.product.device", "").c_str(),
            "getprop(\"ro.product.device\")",
@@ -317,13 +350,12 @@
   ASSERT_EQ(0, OpenArchive(zip_path.c_str(), &handle));
 
   // Need to set up the ziphandle.
-  UpdaterInfo updater_info;
-  updater_info.package_zip = handle;
+  SetUpdaterOtaPackageHandle(handle);
 
   // Two-argument version.
   TemporaryFile temp_file1;
   std::string script("package_extract_file(\"a.txt\", \"" + std::string(temp_file1.path) + "\")");
-  expect("t", script, kNoCause, &updater_info);
+  expect("t", script, kNoCause, &updater_);
 
   // Verify the extracted entry.
   std::string data;
@@ -332,32 +364,30 @@
 
   // Now extract another entry to the same location, which should overwrite.
   script = "package_extract_file(\"b.txt\", \"" + std::string(temp_file1.path) + "\")";
-  expect("t", script, kNoCause, &updater_info);
+  expect("t", script, kNoCause, &updater_);
 
   ASSERT_TRUE(android::base::ReadFileToString(temp_file1.path, &data));
   ASSERT_EQ(kBTxtContents, data);
 
   // Missing zip entry. The two-argument version doesn't abort.
   script = "package_extract_file(\"doesntexist\", \"" + std::string(temp_file1.path) + "\")";
-  expect("", script, kNoCause, &updater_info);
+  expect("", script, kNoCause, &updater_);
 
   // Extract to /dev/full should fail.
   script = "package_extract_file(\"a.txt\", \"/dev/full\")";
-  expect("", script, kNoCause, &updater_info);
+  expect("", script, kNoCause, &updater_);
 
   // One-argument version. package_extract_file() gives a VAL_BLOB, which needs to be converted to
   // VAL_STRING for equality test.
   script = "blob_to_string(package_extract_file(\"a.txt\")) == \"" + kATxtContents + "\"";
-  expect("t", script, kNoCause, &updater_info);
+  expect("t", script, kNoCause, &updater_);
 
   script = "blob_to_string(package_extract_file(\"b.txt\")) == \"" + kBTxtContents + "\"";
-  expect("t", script, kNoCause, &updater_info);
+  expect("t", script, kNoCause, &updater_);
 
   // Missing entry. The one-argument version aborts the evaluation.
   script = "package_extract_file(\"doesntexist\")";
-  expect(nullptr, script, kPackageExtractFileFailure, &updater_info);
-
-  CloseArchive(handle);
+  expect(nullptr, script, kPackageExtractFileFailure, &updater_);
 }
 
 TEST_F(UpdaterTest, read_file) {
@@ -563,17 +593,15 @@
   expect(nullptr, "set_progress(\".3.5\")", kArgsParsingFailure);
 
   TemporaryFile tf;
-  UpdaterInfo updater_info;
-  updater_info.cmd_pipe = fdopen(tf.release(), "w");
-  expect(".52", "set_progress(\".52\")", kNoCause, &updater_info);
-  fflush(updater_info.cmd_pipe);
+  SetUpdaterCmdPipe(tf.release());
+  expect(".52", "set_progress(\".52\")", kNoCause, &updater_);
+  FlushUpdaterCommandPipe();
 
   std::string cmd;
   ASSERT_TRUE(android::base::ReadFileToString(tf.path, &cmd));
   ASSERT_EQ(android::base::StringPrintf("set_progress %f\n", .52), cmd);
   // recovery-updater protocol expects 2 tokens ("set_progress <frac>").
   ASSERT_EQ(2U, android::base::Split(cmd, " ").size());
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
 }
 
 TEST_F(UpdaterTest, show_progress) {
@@ -588,17 +616,15 @@
   expect(nullptr, "show_progress(\".3\", \"5a\")", kArgsParsingFailure);
 
   TemporaryFile tf;
-  UpdaterInfo updater_info;
-  updater_info.cmd_pipe = fdopen(tf.release(), "w");
-  expect(".52", "show_progress(\".52\", \"10\")", kNoCause, &updater_info);
-  fflush(updater_info.cmd_pipe);
+  SetUpdaterCmdPipe(tf.release());
+  expect(".52", "show_progress(\".52\", \"10\")", kNoCause, &updater_);
+  FlushUpdaterCommandPipe();
 
   std::string cmd;
   ASSERT_TRUE(android::base::ReadFileToString(tf.path, &cmd));
   ASSERT_EQ(android::base::StringPrintf("progress %f %d\n", .52, 10), cmd);
   // recovery-updater protocol expects 3 tokens ("progress <frac> <secs>").
   ASSERT_EQ(3U, android::base::Split(cmd, " ").size());
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
 }
 
 TEST_F(UpdaterTest, block_image_update_parsing_error) {
@@ -993,44 +1019,20 @@
   ASSERT_EQ(-1, access(last_command_file_.c_str(), R_OK));
 }
 
-class ResumableUpdaterTest : public testing::TestWithParam<size_t> {
+class ResumableUpdaterTest : public UpdaterTestBase, public testing::TestWithParam<size_t> {
  protected:
   void SetUp() override {
-    RegisterBuiltins();
-    RegisterInstallFunctions();
-    RegisterBlockImageFunctions();
-
-    Paths::Get().set_cache_temp_source(temp_saved_source_.path);
-    Paths::Get().set_last_command_file(temp_last_command_.path);
-    Paths::Get().set_stash_directory_base(temp_stash_base_.path);
-
+    UpdaterTestBase::SetUp();
     // Enable a special command "abort" to simulate interruption.
     Command::abort_allowed_ = true;
-
     index_ = GetParam();
-    image_file_ = image_temp_file_.path;
-    last_command_file_ = temp_last_command_.path;
   }
 
   void TearDown() override {
-    // Clean up the last_command_file if any.
-    ASSERT_TRUE(android::base::RemoveFileIfExists(last_command_file_));
-
-    // Clear partition updated marker if any.
-    std::string updated_marker{ temp_stash_base_.path };
-    updated_marker += "/" + GetSha1(image_temp_file_.path) + ".UPDATED";
-    ASSERT_TRUE(android::base::RemoveFileIfExists(updated_marker));
+    UpdaterTestBase::TearDown();
   }
 
-  TemporaryFile temp_saved_source_;
-  TemporaryDir temp_stash_base_;
-  std::string last_command_file_;
-  std::string image_file_;
   size_t index_;
-
- private:
-  TemporaryFile temp_last_command_;
-  TemporaryFile image_temp_file_;
 };
 
 static std::string g_source_image;
diff --git a/tests/component/verifier_test.cpp b/tests/unit/verifier_test.cpp
similarity index 100%
rename from tests/component/verifier_test.cpp
rename to tests/unit/verifier_test.cpp
diff --git a/tests/unit/zip_test.cpp b/tests/unit/zip_test.cpp
index dfe617e..0753d64 100644
--- a/tests/unit/zip_test.cpp
+++ b/tests/unit/zip_test.cpp
@@ -37,10 +37,9 @@
   ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_path.c_str(), &handle));
 
   static constexpr const char* BINARY_PATH = "META-INF/com/google/android/update-binary";
-  ZipString binary_path(BINARY_PATH);
   ZipEntry binary_entry;
   // Make sure the package opens correctly and its entry can be read.
-  ASSERT_EQ(0, FindEntry(handle, binary_path, &binary_entry));
+  ASSERT_EQ(0, FindEntry(handle, BINARY_PATH, &binary_entry));
 
   TemporaryFile tmp_binary;
   ASSERT_NE(-1, tmp_binary.fd);
diff --git a/tools/image_generator/Android.bp b/tools/image_generator/Android.bp
index 2afdd5a..8300040 100644
--- a/tools/image_generator/Android.bp
+++ b/tools/image_generator/Android.bp
@@ -19,7 +19,7 @@
 
     static_libs: [
         "commons-cli-1.2",
-        "icu4j-host",
+        "icu4j",
     ],
 
     srcs: [
diff --git a/tools/recovery_l10n/res/values-gl/strings.xml b/tools/recovery_l10n/res/values-gl/strings.xml
index e6f2ffd..e51b36d 100644
--- a/tools/recovery_l10n/res/values-gl/strings.xml
+++ b/tools/recovery_l10n/res/values-gl/strings.xml
@@ -6,9 +6,9 @@
     <string name="recovery_no_command" msgid="4465476568623024327">"Non hai ningún comando"</string>
     <string name="recovery_error" msgid="5748178989622716736">"Erro"</string>
     <string name="recovery_installing_security" msgid="9184031299717114342">"Instalando actualización de seguranza"</string>
-    <string name="recovery_wipe_data_menu_header" msgid="550255032058254478">"Non se puido cargar o sistema Android. Os teus datos poden estar danados. Se segue aparecendo esta mensaxe, pode ser necesario restablecer os datos de fábrica e borrar todos os datos do usuario almacenados neste dispositivo."</string>
+    <string name="recovery_wipe_data_menu_header" msgid="550255032058254478">"Non se puido cargar o sistema Android. Os teus datos poden estar danados. Se segue aparecendo esta mensaxe, pode ser necesario restablecer os datos de fábrica e borrar todos os datos de usuario almacenados neste dispositivo."</string>
     <string name="recovery_try_again" msgid="7168248750158873496">"Tentar de novo"</string>
     <string name="recovery_factory_data_reset" msgid="7321351565602894783">"Restablecemento dos datos de fábrica"</string>
-    <string name="recovery_wipe_data_confirmation" msgid="5439823343348043954">"Queres borrar todos os datos do usuario?\n\n ESTA ACCIÓN NON SE PODE DESFACER."</string>
+    <string name="recovery_wipe_data_confirmation" msgid="5439823343348043954">"Queres borrar todos os datos de usuario?\n\n ESTA ACCIÓN NON SE PODE DESFACER."</string>
     <string name="recovery_cancel_wipe_data" msgid="66987687653647384">"Cancelar"</string>
 </resources>
diff --git a/tools/recovery_l10n/res/values-in/strings.xml b/tools/recovery_l10n/res/values-in/strings.xml
index 43c9deb..15a78ec 100644
--- a/tools/recovery_l10n/res/values-in/strings.xml
+++ b/tools/recovery_l10n/res/values-in/strings.xml
@@ -9,6 +9,6 @@
     <string name="recovery_wipe_data_menu_header" msgid="550255032058254478">"Tidak dapat memuat sistem Android. Data Anda mungkin rusak. Jika terus mendapatkan pesan ini, Anda mungkin perlu melakukan reset ke setelan pabrik dan menghapus semua data pengguna yang disimpan di perangkat ini."</string>
     <string name="recovery_try_again" msgid="7168248750158873496">"Coba lagi"</string>
     <string name="recovery_factory_data_reset" msgid="7321351565602894783">"Reset ke setelan pabrik"</string>
-    <string name="recovery_wipe_data_confirmation" msgid="5439823343348043954">"Hapus total semua data pengguna?\n\n TINDAKAN INI TIDAK DAPAT DIURUNGKAN!"</string>
+    <string name="recovery_wipe_data_confirmation" msgid="5439823343348043954">"Wipe semua data pengguna?\n\n TINDAKAN INI TIDAK DAPAT DIURUNGKAN!"</string>
     <string name="recovery_cancel_wipe_data" msgid="66987687653647384">"Batal"</string>
 </resources>
diff --git a/tools/recovery_l10n/res/values-ja/strings.xml b/tools/recovery_l10n/res/values-ja/strings.xml
index 2d6c0ab..3d66372 100644
--- a/tools/recovery_l10n/res/values-ja/strings.xml
+++ b/tools/recovery_l10n/res/values-ja/strings.xml
@@ -6,7 +6,7 @@
     <string name="recovery_no_command" msgid="4465476568623024327">"コマンドが指定されていません"</string>
     <string name="recovery_error" msgid="5748178989622716736">"エラーが発生しました。"</string>
     <string name="recovery_installing_security" msgid="9184031299717114342">"セキュリティ アップデートをインストールしています"</string>
-    <string name="recovery_wipe_data_menu_header" msgid="550255032058254478">"Android システムを読み込めません。データが破損している可能性があります。このメッセージが引き続き表示される場合は、データの初期化を行い、このデバイスに保存されているすべてのユーザー データを消去することが必要な場合があります。"</string>
+    <string name="recovery_wipe_data_menu_header" msgid="550255032058254478">"Android システムを読み込めません。データが破損している可能性があります。このメッセージが引き続き表示される場合は、データの初期化を行い、この端末に保存されているすべてのユーザー データを消去することが必要な場合があります。"</string>
     <string name="recovery_try_again" msgid="7168248750158873496">"再試行"</string>
     <string name="recovery_factory_data_reset" msgid="7321351565602894783">"データの初期化"</string>
     <string name="recovery_wipe_data_confirmation" msgid="5439823343348043954">"すべてのユーザー データをワイプしますか？\n\nこの操作は元に戻せません。"</string>
diff --git a/updater/Android.bp b/updater/Android.bp
index b80cdb3..b279068 100644
--- a/updater/Android.bp
+++ b/updater/Android.bp
@@ -30,7 +30,6 @@
         "libfec",
         "libfec_rs",
         "libverity_tree",
-        "libfs_mgr",
         "libgtest_prod",
         "liblog",
         "liblp",
@@ -46,6 +45,14 @@
         "libcrypto_utils",
         "libcutils",
         "libutils",
+    ],
+}
+
+cc_defaults {
+    name: "libupdater_device_defaults",
+
+    static_libs: [
+        "libfs_mgr",
         "libtune2fs",
 
         "libext2_com_err",
@@ -54,11 +61,13 @@
         "libext2_uuid",
         "libext2_e2p",
         "libext2fs",
-    ],
+    ]
 }
 
 cc_library_static {
-    name: "libupdater",
+    name: "libupdater_core",
+
+    host_supported: true,
 
     defaults: [
         "recovery_defaults",
@@ -68,8 +77,37 @@
     srcs: [
         "blockimg.cpp",
         "commands.cpp",
-        "dynamic_partitions.cpp",
         "install.cpp",
+        "updater.cpp",
+    ],
+
+    target: {
+        darwin: {
+            enabled: false,
+        },
+    },
+
+    export_include_dirs: [
+        "include",
+    ],
+}
+
+cc_library_static {
+    name: "libupdater_device",
+
+    defaults: [
+        "recovery_defaults",
+        "libupdater_defaults",
+        "libupdater_device_defaults",
+    ],
+
+    srcs: [
+        "dynamic_partitions.cpp",
+        "updater_runtime.cpp",
+    ],
+
+    static_libs: [
+        "libupdater_core",
     ],
 
     include_dirs: [
@@ -80,3 +118,32 @@
         "include",
     ],
 }
+
+cc_library_host_static {
+    name: "libupdater_host",
+
+    defaults: [
+        "recovery_defaults",
+        "libupdater_defaults",
+    ],
+
+    srcs: [
+        "simulator_runtime.cpp",
+        "target_files.cpp",
+    ],
+
+    static_libs: [
+        "libupdater_core",
+        "libfstab",
+    ],
+
+    target: {
+        darwin: {
+            enabled: false,
+        },
+    },
+
+    export_include_dirs: [
+        "include",
+    ],
+}
diff --git a/updater/Android.mk b/updater/Android.mk
index c7a6ba9..e969d1c 100644
--- a/updater/Android.mk
+++ b/updater/Android.mk
@@ -33,7 +33,6 @@
     libfec \
     libfec_rs \
     libverity_tree \
-    libfs_mgr \
     libgtest_prod \
     liblog \
     liblp \
@@ -48,9 +47,24 @@
     libcrypto \
     libcrypto_utils \
     libcutils \
-    libutils \
-    libtune2fs \
-    $(tune2fs_static_libraries)
+    libutils
+
+
+# Each library in TARGET_RECOVERY_UPDATER_LIBS should have a function
+# named "Register_<libname>()".  Here we emit a little C function that
+# gets #included by updater.cpp.  It calls all those registration
+# functions.
+# $(1): the path to the register.inc file
+# $(2): a list of TARGET_RECOVERY_UPDATER_LIBS
+define generate-register-inc
+    $(hide) mkdir -p $(dir $(1))
+    $(hide) echo "" > $(1)
+    $(hide) $(foreach lib,$(2),echo "extern void Register_$(lib)(void);" >> $(1);)
+    $(hide) echo "void RegisterDeviceExtensions() {" >> $(1)
+    $(hide) $(foreach lib,$(2),echo "  Register_$(lib)();" >> $(1);)
+    $(hide) echo "}" >> $(1)
+endef
+
 
 # updater (static executable)
 # ===============================
@@ -59,7 +73,7 @@
 LOCAL_MODULE := updater
 
 LOCAL_SRC_FILES := \
-    updater.cpp
+    updater_main.cpp
 
 LOCAL_C_INCLUDES := \
     $(LOCAL_PATH)/include
@@ -69,33 +83,26 @@
     -Werror
 
 LOCAL_STATIC_LIBRARIES := \
-    libupdater \
+    libupdater_device \
+    libupdater_core \
     $(TARGET_RECOVERY_UPDATER_LIBS) \
     $(TARGET_RECOVERY_UPDATER_EXTRA_LIBS) \
-    $(updater_common_static_libraries)
+    $(updater_common_static_libraries) \
+    libfs_mgr \
+    libtune2fs \
+    $(tune2fs_static_libraries)
 
-# Each library in TARGET_RECOVERY_UPDATER_LIBS should have a function
-# named "Register_<libname>()".  Here we emit a little C function that
-# gets #included by updater.c.  It calls all those registration
-# functions.
+LOCAL_MODULE_CLASS := EXECUTABLES
+inc := $(call local-generated-sources-dir)/register.inc
 
 # Devices can also add libraries to TARGET_RECOVERY_UPDATER_EXTRA_LIBS.
 # These libs are also linked in with updater, but we don't try to call
 # any sort of registration function for these.  Use this variable for
 # any subsidiary static libraries required for your registered
 # extension libs.
-
-LOCAL_MODULE_CLASS := EXECUTABLES
-inc := $(call local-generated-sources-dir)/register.inc
-
 $(inc) : libs := $(TARGET_RECOVERY_UPDATER_LIBS)
 $(inc) :
-	$(hide) mkdir -p $(dir $@)
-	$(hide) echo "" > $@
-	$(hide) $(foreach lib,$(libs),echo "extern void Register_$(lib)(void);" >> $@;)
-	$(hide) echo "void RegisterDeviceExtensions() {" >> $@
-	$(hide) $(foreach lib,$(libs),echo "  Register_$(lib)();" >> $@;)
-	$(hide) echo "}" >> $@
+	$(call generate-register-inc,$@,$(libs))
 
 LOCAL_GENERATED_SOURCES := $(inc)
 
@@ -104,3 +111,42 @@
 LOCAL_FORCE_STATIC_EXECUTABLE := true
 
 include $(BUILD_EXECUTABLE)
+
+
+# update_host_simulator (static executable)
+# ===============================
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := update_host_simulator
+LOCAL_MODULE_HOST_OS := linux
+
+LOCAL_SRC_FILES := \
+    update_simulator_main.cpp
+
+LOCAL_C_INCLUDES := \
+    $(LOCAL_PATH)/include
+
+LOCAL_CFLAGS := \
+    -Wall \
+    -Werror
+
+LOCAL_STATIC_LIBRARIES := \
+    libupdater_host \
+    libupdater_core \
+    $(TARGET_RECOVERY_UPDATER_HOST_LIBS) \
+    $(TARGET_RECOVERY_UPDATER_HOST_EXTRA_LIBS) \
+    $(updater_common_static_libraries) \
+    libfstab
+
+LOCAL_MODULE_CLASS := EXECUTABLES
+inc := $(call local-generated-sources-dir)/register.inc
+
+$(inc) : libs := $(TARGET_RECOVERY_UPDATER_HOST_LIBS)
+$(inc) :
+	$(call generate-register-inc,$@,$(libs))
+
+LOCAL_GENERATED_SOURCES := $(inc)
+
+inc :=
+
+include $(BUILD_HOST_EXECUTABLE)
diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index 07c3c7b..2d41f61 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -42,17 +42,18 @@
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
+#include <android-base/stringprintf.h>
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <applypatch/applypatch.h>
 #include <brotli/decode.h>
 #include <fec/io.h>
 #include <openssl/sha.h>
-#include <private/android_filesystem_config.h>
 #include <verity/hash_tree_builder.h>
 #include <ziparchive/zip_archive.h>
 
 #include "edify/expr.h"
+#include "edify/updater_interface.h"
 #include "otautil/dirutil.h"
 #include "otautil/error_code.h"
 #include "otautil/paths.h"
@@ -60,12 +61,16 @@
 #include "otautil/rangeset.h"
 #include "private/commands.h"
 #include "updater/install.h"
-#include "updater/updater.h"
 
-// Set this to 0 to interpret 'erase' transfers to mean do a
-// BLKDISCARD ioctl (the normal behavior).  Set to 1 to interpret
-// erase to mean fill the region with zeroes.
+#ifdef __ANDROID__
+#include <private/android_filesystem_config.h>
+// Set this to 0 to interpret 'erase' transfers to mean do a BLKDISCARD ioctl (the normal behavior).
+// Set to 1 to interpret erase to mean fill the region with zeroes.
 #define DEBUG_ERASE  0
+#else
+#define DEBUG_ERASE 1
+#define AID_SYSTEM -1
+#endif  // __ANDROID__
 
 static constexpr size_t BLOCKSIZE = 4096;
 static constexpr mode_t STASH_DIRECTORY_MODE = 0700;
@@ -1668,42 +1673,43 @@
     return StringValue("");
   }
 
-  UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
-  if (ui == nullptr) {
+  auto updater = state->updater;
+  auto block_device_path = updater->FindBlockDeviceName(blockdev_filename->data);
+  if (block_device_path.empty()) {
+    LOG(ERROR) << "Block device path for " << blockdev_filename->data << " not found. " << name
+               << " failed.";
     return StringValue("");
   }
 
-  FILE* cmd_pipe = ui->cmd_pipe;
-  ZipArchiveHandle za = ui->package_zip;
-
-  if (cmd_pipe == nullptr || za == nullptr) {
+  ZipArchiveHandle za = updater->GetPackageHandle();
+  if (za == nullptr) {
     return StringValue("");
   }
 
-  ZipString path_data(patch_data_fn->data.c_str());
+  std::string_view path_data(patch_data_fn->data);
   ZipEntry patch_entry;
   if (FindEntry(za, path_data, &patch_entry) != 0) {
     LOG(ERROR) << name << "(): no file \"" << patch_data_fn->data << "\" in package";
     return StringValue("");
   }
+  params.patch_start = updater->GetMappedPackageAddress() + patch_entry.offset;
 
-  params.patch_start = ui->package_zip_addr + patch_entry.offset;
-  ZipString new_data(new_data_fn->data.c_str());
+  std::string_view new_data(new_data_fn->data);
   ZipEntry new_entry;
   if (FindEntry(za, new_data, &new_entry) != 0) {
     LOG(ERROR) << name << "(): no file \"" << new_data_fn->data << "\" in package";
     return StringValue("");
   }
 
-  params.fd.reset(TEMP_FAILURE_RETRY(open(blockdev_filename->data.c_str(), O_RDWR)));
+  params.fd.reset(TEMP_FAILURE_RETRY(open(block_device_path.c_str(), O_RDWR)));
   if (params.fd == -1) {
     failure_type = errno == EIO ? kEioFailure : kFileOpenFailure;
-    PLOG(ERROR) << "open \"" << blockdev_filename->data << "\" failed";
+    PLOG(ERROR) << "open \"" << block_device_path << "\" failed";
     return StringValue("");
   }
 
   uint8_t digest[SHA_DIGEST_LENGTH];
-  if (!Sha1DevicePath(blockdev_filename->data, digest)) {
+  if (!Sha1DevicePath(block_device_path, digest)) {
     return StringValue("");
   }
   params.stashbase = print_sha1(digest);
@@ -1716,8 +1722,7 @@
     struct stat sb;
     int result = stat(updated_marker.c_str(), &sb);
     if (result == 0) {
-      LOG(INFO) << "Skipping already updated partition " << blockdev_filename->data
-                << " based on marker";
+      LOG(INFO) << "Skipping already updated partition " << block_device_path << " based on marker";
       return StringValue("t");
     }
   } else {
@@ -1887,8 +1892,10 @@
         LOG(WARNING) << "Failed to update the last command file.";
       }
 
-      fprintf(cmd_pipe, "set_progress %.4f\n", static_cast<double>(params.written) / total_blocks);
-      fflush(cmd_pipe);
+      updater->WriteToCommandPipe(
+          android::base::StringPrintf("set_progress %.4f",
+                                      static_cast<double>(params.written) / total_blocks),
+          true);
     }
   }
 
@@ -1913,13 +1920,15 @@
       LOG(INFO) << "stashed " << params.stashed << " blocks";
       LOG(INFO) << "max alloc needed was " << params.buffer.size();
 
-      const char* partition = strrchr(blockdev_filename->data.c_str(), '/');
+      const char* partition = strrchr(block_device_path.c_str(), '/');
       if (partition != nullptr && *(partition + 1) != 0) {
-        fprintf(cmd_pipe, "log bytes_written_%s: %" PRIu64 "\n", partition + 1,
-                static_cast<uint64_t>(params.written) * BLOCKSIZE);
-        fprintf(cmd_pipe, "log bytes_stashed_%s: %" PRIu64 "\n", partition + 1,
-                static_cast<uint64_t>(params.stashed) * BLOCKSIZE);
-        fflush(cmd_pipe);
+        updater->WriteToCommandPipe(
+            android::base::StringPrintf("log bytes_written_%s: %" PRIu64, partition + 1,
+                                        static_cast<uint64_t>(params.written) * BLOCKSIZE));
+        updater->WriteToCommandPipe(
+            android::base::StringPrintf("log bytes_stashed_%s: %" PRIu64, partition + 1,
+                                        static_cast<uint64_t>(params.stashed) * BLOCKSIZE),
+            true);
       }
       // Delete stash only after successfully completing the update, as it may contain blocks needed
       // to complete the update later.
@@ -2019,7 +2028,7 @@
     // clang-format off
     { Command::Type::ABORT,             PerformCommandAbort },
     { Command::Type::BSDIFF,            PerformCommandDiff },
-    { Command::Type::COMPUTE_HASH_TREE, PerformCommandComputeHashTree },
+    { Command::Type::COMPUTE_HASH_TREE, nullptr },
     { Command::Type::ERASE,             nullptr },
     { Command::Type::FREE,              PerformCommandFree },
     { Command::Type::IMGDIFF,           PerformCommandDiff },
@@ -2079,10 +2088,17 @@
     return StringValue("");
   }
 
-  android::base::unique_fd fd(open(blockdev_filename->data.c_str(), O_RDWR));
+  auto block_device_path = state->updater->FindBlockDeviceName(blockdev_filename->data);
+  if (block_device_path.empty()) {
+    LOG(ERROR) << "Block device path for " << blockdev_filename->data << " not found. " << name
+               << " failed.";
+    return StringValue("");
+  }
+
+  android::base::unique_fd fd(open(block_device_path.c_str(), O_RDWR));
   if (fd == -1) {
     CauseCode cause_code = errno == EIO ? kEioFailure : kFileOpenFailure;
-    ErrorAbort(state, cause_code, "open \"%s\" failed: %s", blockdev_filename->data.c_str(),
+    ErrorAbort(state, cause_code, "open \"%s\" failed: %s", block_device_path.c_str(),
                strerror(errno));
     return StringValue("");
   }
@@ -2096,7 +2112,7 @@
   std::vector<uint8_t> buffer(BLOCKSIZE);
   for (const auto& [begin, end] : rs) {
     if (!check_lseek(fd, static_cast<off64_t>(begin) * BLOCKSIZE, SEEK_SET)) {
-      ErrorAbort(state, kLseekFailure, "failed to seek %s: %s", blockdev_filename->data.c_str(),
+      ErrorAbort(state, kLseekFailure, "failed to seek %s: %s", block_device_path.c_str(),
                  strerror(errno));
       return StringValue("");
     }
@@ -2104,7 +2120,7 @@
     for (size_t j = begin; j < end; ++j) {
       if (!android::base::ReadFully(fd, buffer.data(), BLOCKSIZE)) {
         CauseCode cause_code = errno == EIO ? kEioFailure : kFreadFailure;
-        ErrorAbort(state, cause_code, "failed to read %s: %s", blockdev_filename->data.c_str(),
+        ErrorAbort(state, cause_code, "failed to read %s: %s", block_device_path.c_str(),
                    strerror(errno));
         return StringValue("");
       }
@@ -2143,10 +2159,17 @@
     return StringValue("");
   }
 
-  android::base::unique_fd fd(open(arg_filename->data.c_str(), O_RDONLY));
+  auto block_device_path = state->updater->FindBlockDeviceName(arg_filename->data);
+  if (block_device_path.empty()) {
+    LOG(ERROR) << "Block device path for " << arg_filename->data << " not found. " << name
+               << " failed.";
+    return StringValue("");
+  }
+
+  android::base::unique_fd fd(open(block_device_path.c_str(), O_RDONLY));
   if (fd == -1) {
     CauseCode cause_code = errno == EIO ? kEioFailure : kFileOpenFailure;
-    ErrorAbort(state, cause_code, "open \"%s\" failed: %s", arg_filename->data.c_str(),
+    ErrorAbort(state, cause_code, "open \"%s\" failed: %s", block_device_path.c_str(),
                strerror(errno));
     return StringValue("");
   }
@@ -2156,7 +2179,7 @@
 
   if (ReadBlocks(blk0, &block0_buffer, fd) == -1) {
     CauseCode cause_code = errno == EIO ? kEioFailure : kFreadFailure;
-    ErrorAbort(state, cause_code, "failed to read %s: %s", arg_filename->data.c_str(),
+    ErrorAbort(state, cause_code, "failed to read %s: %s", block_device_path.c_str(),
                strerror(errno));
     return StringValue("");
   }
@@ -2172,8 +2195,10 @@
   uint16_t mount_count = *reinterpret_cast<uint16_t*>(&block0_buffer[0x400 + 0x34]);
 
   if (mount_count > 0) {
-    uiPrintf(state, "Device was remounted R/W %" PRIu16 " times", mount_count);
-    uiPrintf(state, "Last remount happened on %s", ctime(&mount_time));
+    state->updater->UiPrint(
+        android::base::StringPrintf("Device was remounted R/W %" PRIu16 " times", mount_count));
+    state->updater->UiPrint(
+        android::base::StringPrintf("Last remount happened on %s", ctime(&mount_time)));
   }
 
   return StringValue("t");
@@ -2209,14 +2234,21 @@
     return StringValue("");
   }
 
+  auto block_device_path = state->updater->FindBlockDeviceName(filename->data);
+  if (block_device_path.empty()) {
+    LOG(ERROR) << "Block device path for " << filename->data << " not found. " << name
+               << " failed.";
+    return StringValue("");
+  }
+
   // Output notice to log when recover is attempted
-  LOG(INFO) << filename->data << " image corrupted, attempting to recover...";
+  LOG(INFO) << block_device_path << " image corrupted, attempting to recover...";
 
   // When opened with O_RDWR, libfec rewrites corrupted blocks when they are read
-  fec::io fh(filename->data, O_RDWR);
+  fec::io fh(block_device_path, O_RDWR);
 
   if (!fh) {
-    ErrorAbort(state, kLibfecFailure, "fec_open \"%s\" failed: %s", filename->data.c_str(),
+    ErrorAbort(state, kLibfecFailure, "fec_open \"%s\" failed: %s", block_device_path.c_str(),
                strerror(errno));
     return StringValue("");
   }
@@ -2242,7 +2274,7 @@
 
       if (fh.pread(buffer, BLOCKSIZE, static_cast<off64_t>(j) * BLOCKSIZE) != BLOCKSIZE) {
         ErrorAbort(state, kLibfecFailure, "failed to recover %s (block %zu): %s",
-                   filename->data.c_str(), j, strerror(errno));
+                   block_device_path.c_str(), j, strerror(errno));
         return StringValue("");
       }
 
@@ -2258,7 +2290,7 @@
       //     read and check if the errors field value has increased.
     }
   }
-  LOG(INFO) << "..." << filename->data << " image recovered successfully.";
+  LOG(INFO) << "..." << block_device_path << " image recovered successfully.";
   return StringValue("t");
 }
 
diff --git a/updater/include/updater/install.h b/updater/include/updater/install.h
index 8d6ca47..9fe2031 100644
--- a/updater/include/updater/install.h
+++ b/updater/include/updater/install.h
@@ -14,15 +14,6 @@
  * limitations under the License.
  */
 
-#ifndef _UPDATER_INSTALL_H_
-#define _UPDATER_INSTALL_H_
-
-struct State;
+#pragma once
 
 void RegisterInstallFunctions();
-
-// uiPrintf function prints msg to screen as well as logs
-void uiPrintf(State* _Nonnull state, const char* _Nonnull format, ...)
-    __attribute__((__format__(printf, 2, 3)));
-
-#endif
diff --git a/updater/include/updater/simulator_runtime.h b/updater/include/updater/simulator_runtime.h
new file mode 100644
index 0000000..93fa2a4
--- /dev/null
+++ b/updater/include/updater/simulator_runtime.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <map>
+#include <memory>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include "edify/updater_runtime_interface.h"
+#include "updater/target_files.h"
+
+class SimulatorRuntime : public UpdaterRuntimeInterface {
+ public:
+  explicit SimulatorRuntime(TargetFiles* source) : source_(source) {}
+
+  bool IsSimulator() const override {
+    return true;
+  }
+
+  std::string GetProperty(const std::string_view key,
+                          const std::string_view default_value) const override;
+
+  int Mount(const std::string_view location, const std::string_view mount_point,
+            const std::string_view fs_type, const std::string_view mount_options) override;
+  bool IsMounted(const std::string_view mount_point) const override;
+  std::pair<bool, int> Unmount(const std::string_view mount_point) override;
+
+  bool ReadFileToString(const std::string_view filename, std::string* content) const override;
+  bool WriteStringToFile(const std::string_view content,
+                         const std::string_view filename) const override;
+
+  int WipeBlockDevice(const std::string_view filename, size_t len) const override;
+  int RunProgram(const std::vector<std::string>& args, bool is_vfork) const override;
+  int Tune2Fs(const std::vector<std::string>& args) const override;
+
+ private:
+  std::string FindBlockDeviceName(const std::string_view name) const override;
+
+  TargetFiles* source_;
+  std::map<std::string, std::string, std::less<>> mounted_partitions_;
+};
diff --git a/updater/include/updater/target_files.h b/updater/include/updater/target_files.h
new file mode 100644
index 0000000..9ef1a5b
--- /dev/null
+++ b/updater/include/updater/target_files.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <string>
+
+// This class parses a given target file for the build properties and image files. Then it creates
+// and maintains the temporary files to simulate the block devices on host.
+class TargetFiles {
+ public:
+  TargetFiles(std::string path, std::string work_dir)
+      : path_(std::move(path)), work_dir_(std::move(work_dir)) {}
+
+  std::string GetProperty(const std::string_view key, const std::string_view default_value) const;
+
+  std::string FindBlockDeviceName(const std::string_view name) const;
+
+ private:
+  std::string path_;  // Path to the target file.
+
+  std::string work_dir_;  // A temporary directory to store the extracted image files
+};
diff --git a/updater/include/updater/updater.h b/updater/include/updater/updater.h
index f4a2fe8..08816bf 100644
--- a/updater/include/updater/updater.h
+++ b/updater/include/updater/updater.h
@@ -14,22 +14,81 @@
  * limitations under the License.
  */
 
-#ifndef _UPDATER_UPDATER_H_
-#define _UPDATER_UPDATER_H_
+#pragma once
 
+#include <stdint.h>
 #include <stdio.h>
+
+#include <memory>
+#include <string>
+#include <string_view>
+
 #include <ziparchive/zip_archive.h>
 
-typedef struct {
-    FILE* cmd_pipe;
-    ZipArchiveHandle package_zip;
-    int version;
+#include "edify/expr.h"
+#include "edify/updater_interface.h"
+#include "otautil/error_code.h"
+#include "otautil/sysutil.h"
 
-    uint8_t* package_zip_addr;
-    size_t package_zip_len;
-} UpdaterInfo;
+class Updater : public UpdaterInterface {
+ public:
+  explicit Updater(std::unique_ptr<UpdaterRuntimeInterface> run_time)
+      : runtime_(std::move(run_time)) {}
 
-struct selabel_handle;
-extern struct selabel_handle *sehandle;
+  ~Updater() override;
 
-#endif
+  // Memory-maps the OTA package and opens it as a zip file. Also sets up the command pipe and
+  // UpdaterRuntime.
+  bool Init(int fd, const std::string_view package_filename, bool is_retry);
+
+  // Parses and evaluates the updater-script in the OTA package. Reports the error code if the
+  // evaluation fails.
+  bool RunUpdate();
+
+  // Writes the message to command pipe, adds a new line in the end.
+  void WriteToCommandPipe(const std::string_view message, bool flush = false) const override;
+
+  // Sends over the message to recovery to print it on the screen.
+  void UiPrint(const std::string_view message) const override;
+
+  std::string FindBlockDeviceName(const std::string_view name) const override;
+
+  UpdaterRuntimeInterface* GetRuntime() const override {
+    return runtime_.get();
+  }
+  ZipArchiveHandle GetPackageHandle() const override {
+    return package_handle_;
+  }
+  std::string GetResult() const override {
+    return result_;
+  }
+
+  uint8_t* GetMappedPackageAddress() const override {
+    return mapped_package_.addr;
+  }
+
+ private:
+  friend class UpdaterTestBase;
+  friend class UpdaterTest;
+  // Where in the package we expect to find the edify script to execute.
+  // (Note it's "updateR-script", not the older "update-script".)
+  static constexpr const char* SCRIPT_NAME = "META-INF/com/google/android/updater-script";
+
+  // Reads the entry |name| in the zip archive and put the result in |content|.
+  bool ReadEntryToString(ZipArchiveHandle za, const std::string& entry_name, std::string* content);
+
+  // Parses the error code embedded in state->errmsg; and reports the error code and cause code.
+  void ParseAndReportErrorCode(State* state);
+
+  std::unique_ptr<UpdaterRuntimeInterface> runtime_;
+
+  MemMapping mapped_package_;
+  ZipArchiveHandle package_handle_{ nullptr };
+  std::string updater_script_;
+
+  bool is_retry_{ false };
+  std::unique_ptr<FILE, decltype(&fclose)> cmd_pipe_{ nullptr, fclose };
+
+  std::string result_;
+  std::vector<std::string> skipped_functions_;
+};
diff --git a/updater/include/updater/updater_runtime.h b/updater/include/updater/updater_runtime.h
new file mode 100644
index 0000000..e97eb49
--- /dev/null
+++ b/updater/include/updater/updater_runtime.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include "edify/updater_runtime_interface.h"
+
+struct selabel_handle;
+
+class UpdaterRuntime : public UpdaterRuntimeInterface {
+ public:
+  explicit UpdaterRuntime(struct selabel_handle* sehandle) : sehandle_(sehandle) {}
+  ~UpdaterRuntime() override = default;
+
+  bool IsSimulator() const override {
+    return false;
+  }
+
+  std::string GetProperty(const std::string_view key,
+                          const std::string_view default_value) const override;
+
+  std::string FindBlockDeviceName(const std::string_view name) const override;
+
+  int Mount(const std::string_view location, const std::string_view mount_point,
+            const std::string_view fs_type, const std::string_view mount_options) override;
+  bool IsMounted(const std::string_view mount_point) const override;
+  std::pair<bool, int> Unmount(const std::string_view mount_point) override;
+
+  bool ReadFileToString(const std::string_view filename, std::string* content) const override;
+  bool WriteStringToFile(const std::string_view content,
+                         const std::string_view filename) const override;
+
+  int WipeBlockDevice(const std::string_view filename, size_t len) const override;
+  int RunProgram(const std::vector<std::string>& args, bool is_vfork) const override;
+  int Tune2Fs(const std::vector<std::string>& args) const override;
+
+  struct selabel_handle* sehandle_{ nullptr };
+};
diff --git a/updater/install.cpp b/updater/install.cpp
index 20a204a..c82351e 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -53,45 +53,31 @@
 #include <openssl/sha.h>
 #include <selinux/label.h>
 #include <selinux/selinux.h>
-#include <tune2fs.h>
 #include <ziparchive/zip_archive.h>
 
 #include "edify/expr.h"
+#include "edify/updater_interface.h"
+#include "edify/updater_runtime_interface.h"
 #include "otautil/dirutil.h"
 #include "otautil/error_code.h"
 #include "otautil/mounts.h"
 #include "otautil/print_sha1.h"
 #include "otautil/sysutil.h"
-#include "updater/updater.h"
 
-// Send over the buffer to recovery though the command pipe.
-static void uiPrint(State* state, const std::string& buffer) {
-  UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
+#ifndef __ANDROID__
+#include <cutils/memory.h>  // for strlcpy
+#endif
 
-  // "line1\nline2\n" will be split into 3 tokens: "line1", "line2" and "".
-  // So skip sending empty strings to UI.
-  std::vector<std::string> lines = android::base::Split(buffer, "\n");
-  for (auto& line : lines) {
-    if (!line.empty()) {
-      fprintf(ui->cmd_pipe, "ui_print %s\n", line.c_str());
-    }
+static bool UpdateBlockDeviceNameForPartition(UpdaterInterface* updater, Partition* partition) {
+  CHECK(updater);
+  std::string name = updater->FindBlockDeviceName(partition->name);
+  if (name.empty()) {
+    LOG(ERROR) << "Failed to find the block device " << partition->name;
+    return false;
   }
 
-  // On the updater side, we need to dump the contents to stderr (which has
-  // been redirected to the log file). Because the recovery will only print
-  // the contents to screen when processing pipe command ui_print.
-  LOG(INFO) << buffer;
-}
-
-void uiPrintf(State* _Nonnull state, const char* _Nonnull format, ...) {
-  std::string error_msg;
-
-  va_list ap;
-  va_start(ap, format);
-  android::base::StringAppendV(&error_msg, format, ap);
-  va_end(ap);
-
-  uiPrint(state, error_msg);
+  partition->name = std::move(name);
+  return true;
 }
 
 // This is the updater side handler for ui_print() in edify script. Contents will be sent over to
@@ -103,7 +89,7 @@
   }
 
   std::string buffer = android::base::Join(args, "");
-  uiPrint(state, buffer);
+  state->updater->UiPrint(buffer);
   return StringValue(buffer);
 }
 
@@ -129,10 +115,9 @@
     const std::string& zip_path = args[0];
     const std::string& dest_path = args[1];
 
-    ZipArchiveHandle za = static_cast<UpdaterInfo*>(state->cookie)->package_zip;
-    ZipString zip_string_path(zip_path.c_str());
+    ZipArchiveHandle za = state->updater->GetPackageHandle();
     ZipEntry entry;
-    if (FindEntry(za, zip_string_path, &entry) != 0) {
+    if (FindEntry(za, zip_path, &entry) != 0) {
       LOG(ERROR) << name << ": no " << zip_path << " in package";
       return StringValue("");
     }
@@ -173,10 +158,9 @@
     }
     const std::string& zip_path = args[0];
 
-    ZipArchiveHandle za = static_cast<UpdaterInfo*>(state->cookie)->package_zip;
-    ZipString zip_string_path(zip_path.c_str());
+    ZipArchiveHandle za = state->updater->GetPackageHandle();
     ZipEntry entry;
-    if (FindEntry(za, zip_string_path, &entry) != 0) {
+    if (FindEntry(za, zip_path, &entry) != 0) {
       return ErrorAbort(state, kPackageExtractFileFailure, "%s(): no %s in package", name,
                         zip_path.c_str());
     }
@@ -229,6 +213,11 @@
                       args[1].c_str(), err.c_str());
   }
 
+  if (!UpdateBlockDeviceNameForPartition(state->updater, &source) ||
+      !UpdateBlockDeviceNameForPartition(state->updater, &target)) {
+    return StringValue("");
+  }
+
   bool result = PatchPartitionCheck(target, source);
   return StringValue(result ? "t" : "");
 }
@@ -270,6 +259,11 @@
     return ErrorAbort(state, kArgsParsingFailure, "%s(): Invalid patch arg", name);
   }
 
+  if (!UpdateBlockDeviceNameForPartition(state->updater, &source) ||
+      !UpdateBlockDeviceNameForPartition(state->updater, &target)) {
+    return StringValue("");
+  }
+
   bool result = PatchPartition(target, source, *values[0], nullptr);
   return StringValue(result ? "t" : "");
 }
@@ -313,26 +307,11 @@
                       name);
   }
 
-  {
-    char* secontext = nullptr;
-
-    if (sehandle) {
-      selabel_lookup(sehandle, &secontext, mount_point.c_str(), 0755);
-      setfscreatecon(secontext);
-    }
-
-    mkdir(mount_point.c_str(), 0755);
-
-    if (secontext) {
-      freecon(secontext);
-      setfscreatecon(nullptr);
-    }
-  }
-
-  if (mount(location.c_str(), mount_point.c_str(), fs_type.c_str(),
-            MS_NOATIME | MS_NODEV | MS_NODIRATIME, mount_options.c_str()) < 0) {
-    uiPrintf(state, "%s: Failed to mount %s at %s: %s", name, location.c_str(), mount_point.c_str(),
-             strerror(errno));
+  auto updater = state->updater;
+  if (updater->GetRuntime()->Mount(location, mount_point, fs_type, mount_options) != 0) {
+    updater->UiPrint(android::base::StringPrintf("%s: Failed to mount %s at %s: %s", name,
+                                                 location.c_str(), mount_point.c_str(),
+                                                 strerror(errno)));
     return StringValue("");
   }
 
@@ -355,9 +334,8 @@
                       "mount_point argument to unmount() can't be empty");
   }
 
-  scan_mounted_volumes();
-  MountedVolume* vol = find_mounted_volume_by_mount_point(mount_point.c_str());
-  if (vol == nullptr) {
+  auto updater_runtime = state->updater->GetRuntime();
+  if (!updater_runtime->IsMounted(mount_point)) {
     return StringValue("");
   }
 
@@ -378,39 +356,20 @@
                       "mount_point argument to unmount() can't be empty");
   }
 
-  scan_mounted_volumes();
-  MountedVolume* vol = find_mounted_volume_by_mount_point(mount_point.c_str());
-  if (vol == nullptr) {
-    uiPrintf(state, "Failed to unmount %s: No such volume", mount_point.c_str());
+  auto updater = state->updater;
+  auto [mounted, result] = updater->GetRuntime()->Unmount(mount_point);
+  if (!mounted) {
+    updater->UiPrint(
+        android::base::StringPrintf("Failed to unmount %s: No such volume", mount_point.c_str()));
     return nullptr;
-  } else {
-    int ret = unmount_mounted_volume(vol);
-    if (ret != 0) {
-      uiPrintf(state, "Failed to unmount %s: %s", mount_point.c_str(), strerror(errno));
-    }
+  } else if (result != 0) {
+    updater->UiPrint(android::base::StringPrintf("Failed to unmount %s: %s", mount_point.c_str(),
+                                                 strerror(errno)));
   }
 
   return StringValue(mount_point);
 }
 
-static int exec_cmd(const std::vector<std::string>& args) {
-  CHECK(!args.empty());
-  auto argv = StringVectorToNullTerminatedArray(args);
-
-  pid_t child;
-  if ((child = vfork()) == 0) {
-    execv(argv[0], argv.data());
-    _exit(EXIT_FAILURE);
-  }
-
-  int status;
-  waitpid(child, &status, 0);
-  if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
-    LOG(ERROR) << args[0] << " failed with status " << WEXITSTATUS(status);
-  }
-  return WEXITSTATUS(status);
-}
-
 // format(fs_type, partition_type, location, fs_size, mount_point)
 //
 //    fs_type="ext4"  partition_type="EMMC"  location=device  fs_size=<bytes> mount_point=<location>
@@ -455,6 +414,7 @@
                       fs_size.c_str());
   }
 
+  auto updater_runtime = state->updater->GetRuntime();
   if (fs_type == "ext4") {
     std::vector<std::string> mke2fs_args = {
       "/system/bin/mke2fs", "-t", "ext4", "-b", "4096", location
@@ -463,12 +423,13 @@
       mke2fs_args.push_back(std::to_string(size / 4096LL));
     }
 
-    if (auto status = exec_cmd(mke2fs_args); status != 0) {
+    if (auto status = updater_runtime->RunProgram(mke2fs_args, true); status != 0) {
       LOG(ERROR) << name << ": mke2fs failed (" << status << ") on " << location;
       return StringValue("");
     }
 
-    if (auto status = exec_cmd({ "/system/bin/e2fsdroid", "-e", "-a", mount_point, location });
+    if (auto status = updater_runtime->RunProgram(
+            { "/system/bin/e2fsdroid", "-e", "-a", mount_point, location }, true);
         status != 0) {
       LOG(ERROR) << name << ": e2fsdroid failed (" << status << ") on " << location;
       return StringValue("");
@@ -487,12 +448,13 @@
     if (size >= 512) {
       f2fs_args.push_back(std::to_string(size / 512));
     }
-    if (auto status = exec_cmd(f2fs_args); status != 0) {
+    if (auto status = updater_runtime->RunProgram(f2fs_args, true); status != 0) {
       LOG(ERROR) << name << ": make_f2fs failed (" << status << ") on " << location;
       return StringValue("");
     }
 
-    if (auto status = exec_cmd({ "/system/bin/sload_f2fs", "-t", mount_point, location });
+    if (auto status = updater_runtime->RunProgram(
+            { "/system/bin/sload_f2fs", "-t", mount_point, location }, true);
         status != 0) {
       LOG(ERROR) << name << ": sload_f2fs failed (" << status << ") on " << location;
       return StringValue("");
@@ -531,8 +493,7 @@
                       sec_str.c_str());
   }
 
-  UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
-  fprintf(ui->cmd_pipe, "progress %f %d\n", frac, sec);
+  state->updater->WriteToCommandPipe(android::base::StringPrintf("progress %f %d", frac, sec));
 
   return StringValue(frac_str);
 }
@@ -555,8 +516,7 @@
                       frac_str.c_str());
   }
 
-  UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
-  fprintf(ui->cmd_pipe, "set_progress %f\n", frac);
+  state->updater->WriteToCommandPipe(android::base::StringPrintf("set_progress %f", frac));
 
   return StringValue(frac_str);
 }
@@ -569,7 +529,9 @@
   if (!Evaluate(state, argv[0], &key)) {
     return nullptr;
   }
-  std::string value = android::base::GetProperty(key, "");
+
+  auto updater_runtime = state->updater->GetRuntime();
+  std::string value = updater_runtime->GetProperty(key, "");
 
   return StringValue(value);
 }
@@ -594,7 +556,8 @@
   const std::string& key = args[1];
 
   std::string buffer;
-  if (!android::base::ReadFileToString(filename, &buffer)) {
+  auto updater_runtime = state->updater->GetRuntime();
+  if (!updater_runtime->ReadFileToString(filename, &buffer)) {
     ErrorAbort(state, kFreadFailure, "%s: failed to read %s", name, filename.c_str());
     return nullptr;
   }
@@ -655,7 +618,8 @@
     return ErrorAbort(state, kArgsParsingFailure, "%s() expects no args, got %zu", name,
                       argv.size());
   }
-  fprintf(static_cast<UpdaterInfo*>(state->cookie)->cmd_pipe, "wipe_cache\n");
+
+  state->updater->WriteToCommandPipe("wipe_cache");
   return StringValue("t");
 }
 
@@ -669,26 +633,8 @@
     return ErrorAbort(state, kArgsParsingFailure, "%s() Failed to parse the argument(s)", name);
   }
 
-  auto exec_args = StringVectorToNullTerminatedArray(args);
-  LOG(INFO) << "about to run program [" << exec_args[0] << "] with " << argv.size() << " args";
-
-  pid_t child = fork();
-  if (child == 0) {
-    execv(exec_args[0], exec_args.data());
-    PLOG(ERROR) << "run_program: execv failed";
-    _exit(EXIT_FAILURE);
-  }
-
-  int status;
-  waitpid(child, &status, 0);
-  if (WIFEXITED(status)) {
-    if (WEXITSTATUS(status) != 0) {
-      LOG(ERROR) << "run_program: child exited with status " << WEXITSTATUS(status);
-    }
-  } else if (WIFSIGNALED(status)) {
-    LOG(ERROR) << "run_program: child terminated by signal " << WTERMSIG(status);
-  }
-
+  auto updater_runtime = state->updater->GetRuntime();
+  auto status = updater_runtime->RunProgram(args, false);
   return StringValue(std::to_string(status));
 }
 
@@ -706,7 +652,8 @@
   const std::string& filename = args[0];
 
   std::string contents;
-  if (android::base::ReadFileToString(filename, &contents)) {
+  auto updater_runtime = state->updater->GetRuntime();
+  if (updater_runtime->ReadFileToString(filename, &contents)) {
     return new Value(Value::Type::STRING, std::move(contents));
   }
 
@@ -735,12 +682,12 @@
   }
 
   const std::string& value = args[0];
-  if (!android::base::WriteStringToFile(value, filename)) {
+  auto updater_runtime = state->updater->GetRuntime();
+  if (!updater_runtime->WriteStringToFile(value, filename)) {
     PLOG(ERROR) << name << ": Failed to write to \"" << filename << "\"";
     return StringValue("");
-  } else {
-    return StringValue("t");
   }
+  return StringValue("t");
 }
 
 // Immediately reboot the device.  Recovery is not finished normally,
@@ -778,7 +725,7 @@
     return StringValue("");
   }
 
-  reboot("reboot," + property);
+  Reboot(property);
 
   sleep(5);
   return ErrorAbort(state, kRebootFailure, "%s() failed to reboot", name);
@@ -866,16 +813,10 @@
   if (!android::base::ParseUint(len_str.c_str(), &len)) {
     return nullptr;
   }
-  android::base::unique_fd fd(open(filename.c_str(), O_WRONLY));
-  if (fd == -1) {
-    PLOG(ERROR) << "Failed to open " << filename;
-    return StringValue("");
-  }
 
-  // The wipe_block_device function in ext4_utils returns 0 on success and 1
-  // for failure.
-  int status = wipe_block_device(fd, len);
-  return StringValue((status == 0) ? "t" : "");
+  auto updater_runtime = state->updater->GetRuntime();
+  int status = updater_runtime->WipeBlockDevice(filename, len);
+  return StringValue(status == 0 ? "t" : "");
 }
 
 Value* EnableRebootFn(const char* name, State* state, const std::vector<std::unique_ptr<Expr>>& argv) {
@@ -883,8 +824,7 @@
     return ErrorAbort(state, kArgsParsingFailure, "%s() expects no args, got %zu", name,
                       argv.size());
   }
-  UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
-  fprintf(ui->cmd_pipe, "enable_reboot\n");
+  state->updater->WriteToCommandPipe("enable_reboot");
   return StringValue("t");
 }
 
@@ -900,10 +840,8 @@
 
   // tune2fs expects the program name as its first arg.
   args.insert(args.begin(), "tune2fs");
-  auto tune2fs_args = StringVectorToNullTerminatedArray(args);
-
-  // tune2fs changes the filesystem parameters on an ext2 filesystem; it returns 0 on success.
-  if (auto result = tune2fs_main(tune2fs_args.size() - 1, tune2fs_args.data()); result != 0) {
+  auto updater_runtime = state->updater->GetRuntime();
+  if (auto result = updater_runtime->Tune2Fs(args); result != 0) {
     return ErrorAbort(state, kTune2FsFailure, "%s() returned error code %d", name, result);
   }
   return StringValue("t");
diff --git a/updater/simulator_runtime.cpp b/updater/simulator_runtime.cpp
new file mode 100644
index 0000000..c3b3d95
--- /dev/null
+++ b/updater/simulator_runtime.cpp
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "updater/simulator_runtime.h"
+
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <ext4_utils/wipe.h>
+#include <selinux/label.h>
+
+#include "otautil/mounts.h"
+#include "otautil/sysutil.h"
+
+std::string SimulatorRuntime::GetProperty(const std::string_view key,
+                                          const std::string_view default_value) const {
+  return source_->GetProperty(key, default_value);
+}
+
+int SimulatorRuntime::Mount(const std::string_view location, const std::string_view mount_point,
+                            const std::string_view /* fs_type */,
+                            const std::string_view /* mount_options */) {
+  if (auto mounted_location = mounted_partitions_.find(mount_point);
+      mounted_location != mounted_partitions_.end() && mounted_location->second != location) {
+    LOG(ERROR) << mount_point << " has been mounted at " << mounted_location->second;
+    return -1;
+  }
+
+  mounted_partitions_.emplace(mount_point, location);
+  return 0;
+}
+
+bool SimulatorRuntime::IsMounted(const std::string_view mount_point) const {
+  return mounted_partitions_.find(mount_point) != mounted_partitions_.end();
+}
+
+std::pair<bool, int> SimulatorRuntime::Unmount(const std::string_view mount_point) {
+  if (!IsMounted(mount_point)) {
+    return { false, -1 };
+  }
+
+  mounted_partitions_.erase(std::string(mount_point));
+  return { true, 0 };
+}
+
+std::string SimulatorRuntime::FindBlockDeviceName(const std::string_view name) const {
+  return source_->FindBlockDeviceName(name);
+}
+
+// TODO(xunchang) implement the utility functions in simulator.
+int SimulatorRuntime::RunProgram(const std::vector<std::string>& args, bool /* is_vfork */) const {
+  LOG(INFO) << "Running program with args " << android::base::Join(args, " ");
+  return 0;
+}
+
+int SimulatorRuntime::Tune2Fs(const std::vector<std::string>& args) const {
+  LOG(INFO) << "Running Tune2Fs with args " << android::base::Join(args, " ");
+  return 0;
+}
+
+int SimulatorRuntime::WipeBlockDevice(const std::string_view filename, size_t /* len */) const {
+  LOG(INFO) << "SKip wiping block device " << filename;
+  return 0;
+}
+
+bool SimulatorRuntime::ReadFileToString(const std::string_view filename,
+                                        std::string* /* content */) const {
+  LOG(INFO) << "SKip reading filename " << filename;
+  return true;
+}
+
+bool SimulatorRuntime::WriteStringToFile(const std::string_view content,
+                                         const std::string_view filename) const {
+  LOG(INFO) << "SKip writing " << content.size() << " bytes to file " << filename;
+  return true;
+}
diff --git a/updater/target_files.cpp b/updater/target_files.cpp
new file mode 100644
index 0000000..53671dd
--- /dev/null
+++ b/updater/target_files.cpp
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "updater/target_files.h"
+
+std::string TargetFiles::GetProperty(const std::string_view /*key*/,
+                                     const std::string_view default_value) const {
+  return std::string(default_value);
+}
+
+std::string TargetFiles::FindBlockDeviceName(const std::string_view name) const {
+  return std::string(name);
+}
diff --git a/updater/update_simulator_main.cpp b/updater/update_simulator_main.cpp
new file mode 100644
index 0000000..d10453c
--- /dev/null
+++ b/updater/update_simulator_main.cpp
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+
+#include "otautil/error_code.h"
+#include "otautil/paths.h"
+#include "updater/blockimg.h"
+#include "updater/install.h"
+#include "updater/simulator_runtime.h"
+#include "updater/target_files.h"
+#include "updater/updater.h"
+
+int main(int argc, char** argv) {
+  // Write the logs to stdout.
+  android::base::InitLogging(argv, &android::base::StderrLogger);
+
+  if (argc != 3 && argc != 4) {
+    LOG(ERROR) << "unexpected number of arguments: " << argc << std::endl
+               << "Usage: " << argv[0] << " <source_target-file> <ota_package>";
+    return 1;
+  }
+
+  // TODO(xunchang) implement a commandline parser, e.g. it can take an oem property so that the
+  // file_getprop() will return correct value.
+
+  std::string source_target_file = argv[1];
+  std::string package_name = argv[2];
+
+  // Configure edify's functions.
+  RegisterBuiltins();
+  RegisterInstallFunctions();
+  RegisterBlockImageFunctions();
+
+  TemporaryFile temp_saved_source;
+  TemporaryFile temp_last_command;
+  TemporaryDir temp_stash_base;
+
+  Paths::Get().set_cache_temp_source(temp_saved_source.path);
+  Paths::Get().set_last_command_file(temp_last_command.path);
+  Paths::Get().set_stash_directory_base(temp_stash_base.path);
+
+  TemporaryFile cmd_pipe;
+
+  TemporaryDir source_temp_dir;
+  TargetFiles source(source_target_file, source_temp_dir.path);
+
+  Updater updater(std::make_unique<SimulatorRuntime>(&source));
+  if (!updater.Init(cmd_pipe.release(), package_name, false)) {
+    return 1;
+  }
+
+  if (!updater.RunUpdate()) {
+    return 1;
+  }
+
+  LOG(INFO) << "\nscript succeeded, result: " << updater.GetResult();
+
+  return 0;
+}
diff --git a/updater/updater.cpp b/updater/updater.cpp
index 7b5a3f9..8f4a6ed 100644
--- a/updater/updater.cpp
+++ b/updater/updater.cpp
@@ -16,8 +16,6 @@
 
 #include "updater/updater.h"
 
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
@@ -25,198 +23,162 @@
 
 #include <android-base/logging.h>
 #include <android-base/strings.h>
-#include <selinux/android.h>
-#include <selinux/label.h>
-#include <selinux/selinux.h>
-#include <ziparchive/zip_archive.h>
 
-#include "edify/expr.h"
-#include "otautil/dirutil.h"
-#include "otautil/error_code.h"
-#include "otautil/sysutil.h"
-#include "updater/blockimg.h"
-#include "updater/dynamic_partitions.h"
-#include "updater/install.h"
+#include "edify/updater_runtime_interface.h"
 
-// Generated by the makefile, this function defines the
-// RegisterDeviceExtensions() function, which calls all the
-// registration functions for device-specific extensions.
-#include "register.inc"
-
-// Where in the package we expect to find the edify script to execute.
-// (Note it's "updateR-script", not the older "update-script".)
-static constexpr const char* SCRIPT_NAME = "META-INF/com/google/android/updater-script";
-
-struct selabel_handle *sehandle;
-
-static void UpdaterLogger(android::base::LogId /* id */, android::base::LogSeverity /* severity */,
-                          const char* /* tag */, const char* /* file */, unsigned int /* line */,
-                          const char* message) {
-  fprintf(stdout, "%s\n", message);
+Updater::~Updater() {
+  if (package_handle_) {
+    CloseArchive(package_handle_);
+  }
 }
 
-int main(int argc, char** argv) {
-  // Various things log information to stdout or stderr more or less
-  // at random (though we've tried to standardize on stdout).  The
-  // log file makes more sense if buffering is turned off so things
-  // appear in the right order.
-  setbuf(stdout, nullptr);
-  setbuf(stderr, nullptr);
-
-  // We don't have logcat yet under recovery. Update logs will always be written to stdout
-  // (which is redirected to recovery.log).
-  android::base::InitLogging(argv, &UpdaterLogger);
-
-  if (argc != 4 && argc != 5) {
-    LOG(ERROR) << "unexpected number of arguments: " << argc;
-    return 1;
-  }
-
-  char* version = argv[1];
-  if ((version[0] != '1' && version[0] != '2' && version[0] != '3') || version[1] != '\0') {
-    // We support version 1, 2, or 3.
-    LOG(ERROR) << "wrong updater binary API; expected 1, 2, or 3; got " << argv[1];
-    return 2;
-  }
-
+bool Updater::Init(int fd, const std::string_view package_filename, bool is_retry) {
   // Set up the pipe for sending commands back to the parent process.
-
-  int fd = atoi(argv[2]);
-  FILE* cmd_pipe = fdopen(fd, "wb");
-  setlinebuf(cmd_pipe);
-
-  // Extract the script from the package.
-
-  const char* package_filename = argv[3];
-  MemMapping map;
-  if (!map.MapFile(package_filename)) {
-    LOG(ERROR) << "failed to map package " << argv[3];
-    return 3;
-  }
-  ZipArchiveHandle za;
-  int open_err = OpenArchiveFromMemory(map.addr, map.length, argv[3], &za);
-  if (open_err != 0) {
-    LOG(ERROR) << "failed to open package " << argv[3] << ": " << ErrorCodeString(open_err);
-    CloseArchive(za);
-    return 3;
+  cmd_pipe_.reset(fdopen(fd, "wb"));
+  if (!cmd_pipe_) {
+    LOG(ERROR) << "Failed to open the command pipe";
+    return false;
   }
 
-  ZipString script_name(SCRIPT_NAME);
-  ZipEntry script_entry;
-  int find_err = FindEntry(za, script_name, &script_entry);
-  if (find_err != 0) {
-    LOG(ERROR) << "failed to find " << SCRIPT_NAME << " in " << package_filename << ": "
-               << ErrorCodeString(find_err);
-    CloseArchive(za);
-    return 4;
+  setlinebuf(cmd_pipe_.get());
+
+  if (!mapped_package_.MapFile(std::string(package_filename))) {
+    LOG(ERROR) << "failed to map package " << package_filename;
+    return false;
+  }
+  if (int open_err = OpenArchiveFromMemory(mapped_package_.addr, mapped_package_.length,
+                                           std::string(package_filename).c_str(), &package_handle_);
+      open_err != 0) {
+    LOG(ERROR) << "failed to open package " << package_filename << ": "
+               << ErrorCodeString(open_err);
+    return false;
+  }
+  if (!ReadEntryToString(package_handle_, SCRIPT_NAME, &updater_script_)) {
+    return false;
   }
 
-  std::string script;
-  script.resize(script_entry.uncompressed_length);
-  int extract_err = ExtractToMemory(za, &script_entry, reinterpret_cast<uint8_t*>(&script[0]),
-                                    script_entry.uncompressed_length);
-  if (extract_err != 0) {
-    LOG(ERROR) << "failed to read script from package: " << ErrorCodeString(extract_err);
-    CloseArchive(za);
-    return 5;
-  }
+  is_retry_ = is_retry;
 
-  // Configure edify's functions.
+  return true;
+}
 
-  RegisterBuiltins();
-  RegisterInstallFunctions();
-  RegisterBlockImageFunctions();
-  RegisterDynamicPartitionsFunctions();
-  RegisterDeviceExtensions();
+bool Updater::RunUpdate() {
+  CHECK(runtime_);
 
   // Parse the script.
-
   std::unique_ptr<Expr> root;
   int error_count = 0;
-  int error = ParseString(script, &root, &error_count);
+  int error = ParseString(updater_script_, &root, &error_count);
   if (error != 0 || error_count > 0) {
     LOG(ERROR) << error_count << " parse errors";
-    CloseArchive(za);
-    return 6;
-  }
-
-  sehandle = selinux_android_file_context_handle();
-  selinux_android_set_sehandle(sehandle);
-
-  if (!sehandle) {
-    fprintf(cmd_pipe, "ui_print Warning: No file_contexts\n");
+    return false;
   }
 
   // Evaluate the parsed script.
+  State state(updater_script_, this);
+  state.is_retry = is_retry_;
 
-  UpdaterInfo updater_info;
-  updater_info.cmd_pipe = cmd_pipe;
-  updater_info.package_zip = za;
-  updater_info.version = atoi(version);
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
+  bool status = Evaluate(&state, root, &result_);
+  if (status) {
+    fprintf(cmd_pipe_.get(), "ui_print script succeeded: result was [%s]\n", result_.c_str());
+    // Even though the script doesn't abort, still log the cause code if result is empty.
+    if (result_.empty() && state.cause_code != kNoCause) {
+      fprintf(cmd_pipe_.get(), "log cause: %d\n", state.cause_code);
+    }
+    for (const auto& func : skipped_functions_) {
+      LOG(WARNING) << "Skipped executing function " << func;
+    }
+    return true;
+  }
 
-  State state(script, &updater_info);
+  ParseAndReportErrorCode(&state);
+  return false;
+}
 
-  if (argc == 5) {
-    if (strcmp(argv[4], "retry") == 0) {
-      state.is_retry = true;
-    } else {
-      printf("unexpected argument: %s", argv[4]);
+void Updater::WriteToCommandPipe(const std::string_view message, bool flush) const {
+  fprintf(cmd_pipe_.get(), "%s\n", std::string(message).c_str());
+  if (flush) {
+    fflush(cmd_pipe_.get());
+  }
+}
+
+void Updater::UiPrint(const std::string_view message) const {
+  // "line1\nline2\n" will be split into 3 tokens: "line1", "line2" and "".
+  // so skip sending empty strings to ui.
+  std::vector<std::string> lines = android::base::Split(std::string(message), "\n");
+  for (const auto& line : lines) {
+    if (!line.empty()) {
+      fprintf(cmd_pipe_.get(), "ui_print %s\n", line.c_str());
     }
   }
 
-  std::string result;
-  bool status = Evaluate(&state, root, &result);
+  // on the updater side, we need to dump the contents to stderr (which has
+  // been redirected to the log file). because the recovery will only print
+  // the contents to screen when processing pipe command ui_print.
+  LOG(INFO) << message;
+}
 
-  if (!status) {
-    if (state.errmsg.empty()) {
-      LOG(ERROR) << "script aborted (no error message)";
-      fprintf(cmd_pipe, "ui_print script aborted (no error message)\n");
-    } else {
-      LOG(ERROR) << "script aborted: " << state.errmsg;
-      const std::vector<std::string> lines = android::base::Split(state.errmsg, "\n");
-      for (const std::string& line : lines) {
-        // Parse the error code in abort message.
-        // Example: "E30: This package is for bullhead devices."
-        if (!line.empty() && line[0] == 'E') {
-          if (sscanf(line.c_str(), "E%d: ", &state.error_code) != 1) {
-            LOG(ERROR) << "Failed to parse error code: [" << line << "]";
-          }
-        }
-        fprintf(cmd_pipe, "ui_print %s\n", line.c_str());
-      }
-    }
+std::string Updater::FindBlockDeviceName(const std::string_view name) const {
+  return runtime_->FindBlockDeviceName(name);
+}
 
-    // Installation has been aborted. Set the error code to kScriptExecutionFailure unless
-    // a more specific code has been set in errmsg.
-    if (state.error_code == kNoError) {
-      state.error_code = kScriptExecutionFailure;
-    }
-    fprintf(cmd_pipe, "log error: %d\n", state.error_code);
-    // Cause code should provide additional information about the abort.
-    if (state.cause_code != kNoCause) {
-      fprintf(cmd_pipe, "log cause: %d\n", state.cause_code);
-      if (state.cause_code == kPatchApplicationFailure) {
-        LOG(INFO) << "Patch application failed, retry update.";
-        fprintf(cmd_pipe, "retry_update\n");
-      } else if (state.cause_code == kEioFailure) {
-        LOG(INFO) << "Update failed due to EIO, retry update.";
-        fprintf(cmd_pipe, "retry_update\n");
-      }
-    }
-
-    if (updater_info.package_zip) {
-      CloseArchive(updater_info.package_zip);
-    }
-    return 7;
+void Updater::ParseAndReportErrorCode(State* state) {
+  CHECK(state);
+  if (state->errmsg.empty()) {
+    LOG(ERROR) << "script aborted (no error message)";
+    fprintf(cmd_pipe_.get(), "ui_print script aborted (no error message)\n");
   } else {
-    fprintf(cmd_pipe, "ui_print script succeeded: result was [%s]\n", result.c_str());
+    LOG(ERROR) << "script aborted: " << state->errmsg;
+    const std::vector<std::string> lines = android::base::Split(state->errmsg, "\n");
+    for (const std::string& line : lines) {
+      // Parse the error code in abort message.
+      // Example: "E30: This package is for bullhead devices."
+      if (!line.empty() && line[0] == 'E') {
+        if (sscanf(line.c_str(), "E%d: ", &state->error_code) != 1) {
+          LOG(ERROR) << "Failed to parse error code: [" << line << "]";
+        }
+      }
+      fprintf(cmd_pipe_.get(), "ui_print %s\n", line.c_str());
+    }
   }
 
-  if (updater_info.package_zip) {
-    CloseArchive(updater_info.package_zip);
+  // Installation has been aborted. Set the error code to kScriptExecutionFailure unless
+  // a more specific code has been set in errmsg.
+  if (state->error_code == kNoError) {
+    state->error_code = kScriptExecutionFailure;
+  }
+  fprintf(cmd_pipe_.get(), "log error: %d\n", state->error_code);
+  // Cause code should provide additional information about the abort.
+  if (state->cause_code != kNoCause) {
+    fprintf(cmd_pipe_.get(), "log cause: %d\n", state->cause_code);
+    if (state->cause_code == kPatchApplicationFailure) {
+      LOG(INFO) << "Patch application failed, retry update.";
+      fprintf(cmd_pipe_.get(), "retry_update\n");
+    } else if (state->cause_code == kEioFailure) {
+      LOG(INFO) << "Update failed due to EIO, retry update.";
+      fprintf(cmd_pipe_.get(), "retry_update\n");
+    }
+  }
+}
+
+bool Updater::ReadEntryToString(ZipArchiveHandle za, const std::string& entry_name,
+                                std::string* content) {
+  ZipEntry entry;
+  int find_err = FindEntry(za, entry_name, &entry);
+  if (find_err != 0) {
+    LOG(ERROR) << "failed to find " << entry_name
+               << " in the package: " << ErrorCodeString(find_err);
+    return false;
   }
 
-  return 0;
+  content->resize(entry.uncompressed_length);
+  int extract_err = ExtractToMemory(za, &entry, reinterpret_cast<uint8_t*>(&content->at(0)),
+                                    entry.uncompressed_length);
+  if (extract_err != 0) {
+    LOG(ERROR) << "failed to read " << entry_name
+               << " from package: " << ErrorCodeString(extract_err);
+    return false;
+  }
+
+  return true;
 }
diff --git a/updater/updater_main.cpp b/updater/updater_main.cpp
new file mode 100644
index 0000000..055a8ac
--- /dev/null
+++ b/updater/updater_main.cpp
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <string>
+
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <selinux/android.h>
+#include <selinux/label.h>
+#include <selinux/selinux.h>
+
+#include "edify/expr.h"
+#include "updater/blockimg.h"
+#include "updater/dynamic_partitions.h"
+#include "updater/install.h"
+#include "updater/updater.h"
+#include "updater/updater_runtime.h"
+
+// Generated by the makefile, this function defines the
+// RegisterDeviceExtensions() function, which calls all the
+// registration functions for device-specific extensions.
+#include "register.inc"
+
+static void UpdaterLogger(android::base::LogId /* id */, android::base::LogSeverity /* severity */,
+                          const char* /* tag */, const char* /* file */, unsigned int /* line */,
+                          const char* message) {
+  fprintf(stdout, "%s\n", message);
+}
+
+int main(int argc, char** argv) {
+  // Various things log information to stdout or stderr more or less
+  // at random (though we've tried to standardize on stdout).  The
+  // log file makes more sense if buffering is turned off so things
+  // appear in the right order.
+  setbuf(stdout, nullptr);
+  setbuf(stderr, nullptr);
+
+  // We don't have logcat yet under recovery. Update logs will always be written to stdout
+  // (which is redirected to recovery.log).
+  android::base::InitLogging(argv, &UpdaterLogger);
+
+  if (argc != 4 && argc != 5) {
+    LOG(ERROR) << "unexpected number of arguments: " << argc;
+    return 1;
+  }
+
+  char* version = argv[1];
+  if ((version[0] != '1' && version[0] != '2' && version[0] != '3') || version[1] != '\0') {
+    // We support version 1, 2, or 3.
+    LOG(ERROR) << "wrong updater binary API; expected 1, 2, or 3; got " << argv[1];
+    return 1;
+  }
+
+  int fd;
+  if (!android::base::ParseInt(argv[2], &fd)) {
+    LOG(ERROR) << "Failed to parse fd in " << argv[2];
+    return 1;
+  }
+
+  std::string package_name = argv[3];
+
+  bool is_retry = false;
+  if (argc == 5) {
+    if (strcmp(argv[4], "retry") == 0) {
+      is_retry = true;
+    } else {
+      LOG(ERROR) << "unexpected argument: " << argv[4];
+      return 1;
+    }
+  }
+
+  // Configure edify's functions.
+  RegisterBuiltins();
+  RegisterInstallFunctions();
+  RegisterBlockImageFunctions();
+  RegisterDynamicPartitionsFunctions();
+  RegisterDeviceExtensions();
+
+  auto sehandle = selinux_android_file_context_handle();
+  selinux_android_set_sehandle(sehandle);
+
+  Updater updater(std::make_unique<UpdaterRuntime>(sehandle));
+  if (!updater.Init(fd, package_name, is_retry)) {
+    return 1;
+  }
+
+  if (!updater.RunUpdate()) {
+    return 1;
+  }
+
+  return 0;
+}
\ No newline at end of file
diff --git a/updater/updater_runtime.cpp b/updater/updater_runtime.cpp
new file mode 100644
index 0000000..761f999
--- /dev/null
+++ b/updater/updater_runtime.cpp
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "updater/updater_runtime.h"
+
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <ext4_utils/wipe.h>
+#include <selinux/label.h>
+#include <tune2fs.h>
+
+#include "otautil/mounts.h"
+#include "otautil/sysutil.h"
+
+std::string UpdaterRuntime::GetProperty(const std::string_view key,
+                                        const std::string_view default_value) const {
+  return android::base::GetProperty(std::string(key), std::string(default_value));
+}
+
+std::string UpdaterRuntime::FindBlockDeviceName(const std::string_view name) const {
+  return std::string(name);
+}
+
+int UpdaterRuntime::Mount(const std::string_view location, const std::string_view mount_point,
+                          const std::string_view fs_type, const std::string_view mount_options) {
+  std::string mount_point_string(mount_point);
+  char* secontext = nullptr;
+  if (sehandle_) {
+    selabel_lookup(sehandle_, &secontext, mount_point_string.c_str(), 0755);
+    setfscreatecon(secontext);
+  }
+
+  mkdir(mount_point_string.c_str(), 0755);
+
+  if (secontext) {
+    freecon(secontext);
+    setfscreatecon(nullptr);
+  }
+
+  return mount(std::string(location).c_str(), mount_point_string.c_str(),
+               std::string(fs_type).c_str(), MS_NOATIME | MS_NODEV | MS_NODIRATIME,
+               std::string(mount_options).c_str());
+}
+
+bool UpdaterRuntime::IsMounted(const std::string_view mount_point) const {
+  scan_mounted_volumes();
+  MountedVolume* vol = find_mounted_volume_by_mount_point(std::string(mount_point).c_str());
+  return vol != nullptr;
+}
+
+std::pair<bool, int> UpdaterRuntime::Unmount(const std::string_view mount_point) {
+  scan_mounted_volumes();
+  MountedVolume* vol = find_mounted_volume_by_mount_point(std::string(mount_point).c_str());
+  if (vol == nullptr) {
+    return { false, -1 };
+  }
+
+  int ret = unmount_mounted_volume(vol);
+  return { true, ret };
+}
+
+bool UpdaterRuntime::ReadFileToString(const std::string_view filename, std::string* content) const {
+  return android::base::ReadFileToString(std::string(filename), content);
+}
+
+bool UpdaterRuntime::WriteStringToFile(const std::string_view content,
+                                       const std::string_view filename) const {
+  return android::base::WriteStringToFile(std::string(content), std::string(filename));
+}
+
+int UpdaterRuntime::WipeBlockDevice(const std::string_view filename, size_t len) const {
+  android::base::unique_fd fd(open(std::string(filename).c_str(), O_WRONLY));
+  if (fd == -1) {
+    PLOG(ERROR) << "Failed to open " << filename;
+    return false;
+  }
+  // The wipe_block_device function in ext4_utils returns 0 on success and 1 for failure.
+  return wipe_block_device(fd, len);
+}
+
+int UpdaterRuntime::RunProgram(const std::vector<std::string>& args, bool is_vfork) const {
+  CHECK(!args.empty());
+  auto argv = StringVectorToNullTerminatedArray(args);
+  LOG(INFO) << "about to run program [" << args[0] << "] with " << argv.size() << " args";
+
+  pid_t child = is_vfork ? vfork() : fork();
+  if (child == 0) {
+    execv(argv[0], argv.data());
+    PLOG(ERROR) << "run_program: execv failed";
+    _exit(EXIT_FAILURE);
+  }
+
+  int status;
+  waitpid(child, &status, 0);
+  if (WIFEXITED(status)) {
+    if (WEXITSTATUS(status) != 0) {
+      LOG(ERROR) << "run_program: child exited with status " << WEXITSTATUS(status);
+    }
+  } else if (WIFSIGNALED(status)) {
+    LOG(ERROR) << "run_program: child terminated by signal " << WTERMSIG(status);
+  }
+
+  return status;
+}
+
+int UpdaterRuntime::Tune2Fs(const std::vector<std::string>& args) const {
+  auto tune2fs_args = StringVectorToNullTerminatedArray(args);
+  // tune2fs changes the filesystem parameters on an ext2 filesystem; it returns 0 on success.
+  return tune2fs_main(tune2fs_args.size() - 1, tune2fs_args.data());
+}