diff --git a/Android.mk b/Android.mk
index fef5846..6aa91ea 100644
--- a/Android.mk
+++ b/Android.mk
@@ -204,6 +204,5 @@
     $(LOCAL_PATH)/boot_control/Android.mk \
     $(LOCAL_PATH)/minui/Android.mk \
     $(LOCAL_PATH)/tests/Android.mk \
-    $(LOCAL_PATH)/tools/Android.mk \
     $(LOCAL_PATH)/updater/Android.mk \
     $(LOCAL_PATH)/updater_sample/Android.mk \
diff --git a/applypatch/imgdiff.cpp b/applypatch/imgdiff.cpp
index 674cc2b..415d95f 100644
--- a/applypatch/imgdiff.cpp
+++ b/applypatch/imgdiff.cpp
@@ -462,12 +462,12 @@
       target_len_(tgt.GetRawDataLength()),
       target_uncompressed_len_(tgt.DataLengthForPatch()),
       target_compress_level_(tgt.GetCompressLevel()),
-      data_(tgt.DataForPatch(), tgt.DataForPatch() + tgt.DataLengthForPatch()) {}
+      data_(tgt.GetRawData(), tgt.GetRawData() + tgt.GetRawDataLength()) {}
 
 // Return true if raw data is smaller than the patch size.
 bool PatchChunk::RawDataIsSmaller(const ImageChunk& tgt, size_t patch_size) {
   size_t target_len = tgt.GetRawDataLength();
-  return (tgt.GetType() == CHUNK_NORMAL && (target_len <= 160 || target_len < patch_size));
+  return target_len < patch_size || (tgt.GetType() == CHUNK_NORMAL && target_len <= 160);
 }
 
 void PatchChunk::UpdateSourceOffset(const SortedRangeSet& src_range) {
diff --git a/applypatch/imgpatch.cpp b/applypatch/imgpatch.cpp
index c4c2707..2f8f485 100644
--- a/applypatch/imgpatch.cpp
+++ b/applypatch/imgpatch.cpp
@@ -54,6 +54,7 @@
                                             const Value& patch, size_t patch_offset,
                                             const char* deflate_header, SinkFn sink) {
   size_t expected_target_length = static_cast<size_t>(Read8(deflate_header + 32));
+  CHECK_GT(expected_target_length, 0);
   int level = Read4(deflate_header + 40);
   int method = Read4(deflate_header + 44);
   int window_bits = Read4(deflate_header + 48);
diff --git a/applypatch/include/applypatch/imgdiff_image.h b/applypatch/include/applypatch/imgdiff_image.h
index 0848072..6716051 100644
--- a/applypatch/include/applypatch/imgdiff_image.h
+++ b/applypatch/include/applypatch/imgdiff_image.h
@@ -44,6 +44,8 @@
   int GetType() const {
     return type_;
   }
+
+  const uint8_t* GetRawData() const;
   size_t GetRawDataLength() const {
     return raw_data_len_;
   }
@@ -99,7 +101,6 @@
                         bsdiff::SuffixArrayIndexInterface** bsdiff_cache);
 
  private:
-  const uint8_t* GetRawData() const;
   bool TryReconstruction(int level);
 
   int type_;                                    // CHUNK_NORMAL, CHUNK_DEFLATE, CHUNK_RAW
diff --git a/bootloader_message/Android.bp b/bootloader_message/Android.bp
index c81c67b..ab23733 100644
--- a/bootloader_message/Android.bp
+++ b/bootloader_message/Android.bp
@@ -16,6 +16,7 @@
 
 cc_library_static {
     name: "libbootloader_message",
+    recovery_available: true,
     srcs: ["bootloader_message.cpp"],
     cflags: [
         "-Wall",
diff --git a/tests/Android.mk b/tests/Android.mk
index 853ca27..ff42066 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -37,6 +37,7 @@
 
 LOCAL_SRC_FILES := \
     unit/asn1_decoder_test.cpp \
+    unit/commands_test.cpp \
     unit/dirutil_test.cpp \
     unit/locale_test.cpp \
     unit/rangeset_test.cpp \
diff --git a/tests/component/imgdiff_test.cpp b/tests/component/imgdiff_test.cpp
index 6c23def..cb4868a 100644
--- a/tests/component/imgdiff_test.cpp
+++ b/tests/component/imgdiff_test.cpp
@@ -197,12 +197,17 @@
 }
 
 TEST(ImgdiffTest, zip_mode_smoke_compressed) {
+  // Generate 1 block of random data.
+  std::string random_data;
+  random_data.reserve(4096);
+  generate_n(back_inserter(random_data), 4096, []() { return rand() % 256; });
+
   // Construct src and tgt zip files.
   TemporaryFile src_file;
   FILE* src_file_ptr = fdopen(src_file.release(), "wb");
   ZipWriter src_writer(src_file_ptr);
   ASSERT_EQ(0, src_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string src_content("abcdefg");
+  const std::string src_content = random_data;
   ASSERT_EQ(0, src_writer.WriteBytes(src_content.data(), src_content.size()));
   ASSERT_EQ(0, src_writer.FinishEntry());
   ASSERT_EQ(0, src_writer.Finish());
@@ -212,7 +217,7 @@
   FILE* tgt_file_ptr = fdopen(tgt_file.release(), "wb");
   ZipWriter tgt_writer(tgt_file_ptr);
   ASSERT_EQ(0, tgt_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string tgt_content("abcdefgxyz");
+  const std::string tgt_content = random_data + "extra contents";
   ASSERT_EQ(0, tgt_writer.WriteBytes(tgt_content.data(), tgt_content.size()));
   ASSERT_EQ(0, tgt_writer.FinishEntry());
   ASSERT_EQ(0, tgt_writer.Finish());
@@ -245,13 +250,57 @@
   verify_patched_image(src, patch, tgt);
 }
 
+TEST(ImgdiffTest, zip_mode_empty_target) {
+  TemporaryFile src_file;
+  FILE* src_file_ptr = fdopen(src_file.release(), "wb");
+  ZipWriter src_writer(src_file_ptr);
+  ASSERT_EQ(0, src_writer.StartEntry("file1.txt", ZipWriter::kCompress));
+  const std::string src_content = "abcdefg";
+  ASSERT_EQ(0, src_writer.WriteBytes(src_content.data(), src_content.size()));
+  ASSERT_EQ(0, src_writer.FinishEntry());
+  ASSERT_EQ(0, src_writer.Finish());
+  ASSERT_EQ(0, fclose(src_file_ptr));
+
+  // Construct a empty entry in the target zip.
+  TemporaryFile tgt_file;
+  FILE* tgt_file_ptr = fdopen(tgt_file.release(), "wb");
+  ZipWriter tgt_writer(tgt_file_ptr);
+  ASSERT_EQ(0, tgt_writer.StartEntry("file1.txt", ZipWriter::kCompress));
+  const std::string tgt_content;
+  ASSERT_EQ(0, tgt_writer.WriteBytes(tgt_content.data(), tgt_content.size()));
+  ASSERT_EQ(0, tgt_writer.FinishEntry());
+  ASSERT_EQ(0, tgt_writer.Finish());
+
+  // Compute patch.
+  TemporaryFile patch_file;
+  std::vector<const char*> args = {
+    "imgdiff", "-z", src_file.path, tgt_file.path, patch_file.path,
+  };
+  ASSERT_EQ(0, imgdiff(args.size(), args.data()));
+
+  // Verify.
+  std::string tgt;
+  ASSERT_TRUE(android::base::ReadFileToString(tgt_file.path, &tgt));
+  std::string src;
+  ASSERT_TRUE(android::base::ReadFileToString(src_file.path, &src));
+  std::string patch;
+  ASSERT_TRUE(android::base::ReadFileToString(patch_file.path, &patch));
+
+  verify_patched_image(src, patch, tgt);
+}
+
 TEST(ImgdiffTest, zip_mode_smoke_trailer_zeros) {
+  // Generate 1 block of random data.
+  std::string random_data;
+  random_data.reserve(4096);
+  generate_n(back_inserter(random_data), 4096, []() { return rand() % 256; });
+
   // Construct src and tgt zip files.
   TemporaryFile src_file;
   FILE* src_file_ptr = fdopen(src_file.release(), "wb");
   ZipWriter src_writer(src_file_ptr);
   ASSERT_EQ(0, src_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string src_content("abcdefg");
+  const std::string src_content = random_data;
   ASSERT_EQ(0, src_writer.WriteBytes(src_content.data(), src_content.size()));
   ASSERT_EQ(0, src_writer.FinishEntry());
   ASSERT_EQ(0, src_writer.Finish());
@@ -261,7 +310,7 @@
   FILE* tgt_file_ptr = fdopen(tgt_file.release(), "wb");
   ZipWriter tgt_writer(tgt_file_ptr);
   ASSERT_EQ(0, tgt_writer.StartEntry("file1.txt", ZipWriter::kCompress));
-  const std::string tgt_content("abcdefgxyz");
+  const std::string tgt_content = random_data + "abcdefg";
   ASSERT_EQ(0, tgt_writer.WriteBytes(tgt_content.data(), tgt_content.size()));
   ASSERT_EQ(0, tgt_writer.FinishEntry());
   ASSERT_EQ(0, tgt_writer.Finish());
@@ -298,23 +347,19 @@
 }
 
 TEST(ImgdiffTest, image_mode_simple) {
-  // src: "abcdefgh" + gzipped "xyz" (echo -n "xyz" | gzip -f | hd).
-  const std::vector<char> src_data = { 'a',    'b',    'c',    'd',    'e',    'f',    'g',
-                                       'h',    '\x1f', '\x8b', '\x08', '\x00', '\xc4', '\x1e',
-                                       '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xac',
-                                       '\x02', '\x00', '\x67', '\xba', '\x8e', '\xeb', '\x03',
-                                       '\x00', '\x00', '\x00' };
-  const std::string src(src_data.cbegin(), src_data.cend());
+  std::string gzipped_source_path = from_testdata_base("gzipped_source");
+  std::string gzipped_source;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_source_path, &gzipped_source));
+
+  const std::string src = "abcdefg" + gzipped_source;
   TemporaryFile src_file;
   ASSERT_TRUE(android::base::WriteStringToFile(src, src_file.path));
 
-  // tgt: "abcdefgxyz" + gzipped "xxyyzz".
-  const std::vector<char> tgt_data = {
-    'a',    'b',    'c',    'd',    'e',    'f',    'g',    'x',    'y',    'z',    '\x1f', '\x8b',
-    '\x08', '\x00', '\x62', '\x1f', '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xa8', '\xac',
-    '\xac', '\xaa', '\x02', '\x00', '\x96', '\x30', '\x06', '\xb7', '\x06', '\x00', '\x00', '\x00'
-  };
-  const std::string tgt(tgt_data.cbegin(), tgt_data.cend());
+  std::string gzipped_target_path = from_testdata_base("gzipped_target");
+  std::string gzipped_target;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_target_path, &gzipped_target));
+  const std::string tgt = "abcdefgxyz" + gzipped_target;
+
   TemporaryFile tgt_file;
   ASSERT_TRUE(android::base::WriteStringToFile(tgt, tgt_file.path));
 
@@ -404,23 +449,21 @@
 }
 
 TEST(ImgdiffTest, image_mode_merge_chunks) {
-  // src: "abcdefgh" + gzipped "xyz" (echo -n "xyz" | gzip -f | hd).
-  const std::vector<char> src_data = { 'a',    'b',    'c',    'd',    'e',    'f',    'g',
-                                       'h',    '\x1f', '\x8b', '\x08', '\x00', '\xc4', '\x1e',
-                                       '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8', '\xac',
-                                       '\x02', '\x00', '\x67', '\xba', '\x8e', '\xeb', '\x03',
-                                       '\x00', '\x00', '\x00' };
-  const std::string src(src_data.cbegin(), src_data.cend());
+  // src: "abcdefg" + gzipped_source.
+  std::string gzipped_source_path = from_testdata_base("gzipped_source");
+  std::string gzipped_source;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_source_path, &gzipped_source));
+
+  const std::string src = "abcdefg" + gzipped_source;
   TemporaryFile src_file;
   ASSERT_TRUE(android::base::WriteStringToFile(src, src_file.path));
 
-  // tgt: gzipped "xyz" + "abcdefgh".
-  const std::vector<char> tgt_data = {
-    '\x1f', '\x8b', '\x08', '\x00', '\x62', '\x1f', '\x53', '\x58', '\x00', '\x03', '\xab', '\xa8',
-    '\xa8', '\xac', '\xac', '\xaa', '\x02', '\x00', '\x96', '\x30', '\x06', '\xb7', '\x06', '\x00',
-    '\x00', '\x00', 'a',    'b',    'c',    'd',    'e',    'f',    'g',    'x',    'y',    'z'
-  };
-  const std::string tgt(tgt_data.cbegin(), tgt_data.cend());
+  // tgt: gzipped_target + "abcdefgxyz".
+  std::string gzipped_target_path = from_testdata_base("gzipped_target");
+  std::string gzipped_target;
+  ASSERT_TRUE(android::base::ReadFileToString(gzipped_target_path, &gzipped_target));
+
+  const std::string tgt = gzipped_target + "abcdefgxyz";
   TemporaryFile tgt_file;
   ASSERT_TRUE(android::base::WriteStringToFile(tgt, tgt_file.path));
 
diff --git a/tests/component/updater_test.cpp b/tests/component/updater_test.cpp
index 48363a6..de8fafd 100644
--- a/tests/component/updater_test.cpp
+++ b/tests/component/updater_test.cpp
@@ -27,6 +27,8 @@
 #include <vector>
 
 #include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
@@ -48,7 +50,11 @@
 #include "updater/install.h"
 #include "updater/updater.h"
 
-struct selabel_handle *sehandle = nullptr;
+using PackageEntries = std::unordered_map<std::string, std::string>;
+
+static constexpr size_t kTransferListHeaderLines = 4;
+
+struct selabel_handle* sehandle = nullptr;
 
 static void expect(const char* expected, const char* expr_str, CauseCode cause_code,
                    UpdaterInfo* info = nullptr) {
@@ -76,12 +82,12 @@
   ASSERT_EQ(cause_code, state.cause_code);
 }
 
-static void BuildUpdatePackage(const std::unordered_map<std::string, std::string>& entries,
-                               int fd) {
+static void BuildUpdatePackage(const PackageEntries& entries, int fd) {
   FILE* zip_file_ptr = fdopen(fd, "wb");
   ZipWriter zip_writer(zip_file_ptr);
 
   for (const auto& entry : entries) {
+    // All the entries are written as STORED.
     ASSERT_EQ(0, zip_writer.StartEntry(entry.first.c_str(), 0));
     if (!entry.second.empty()) {
       ASSERT_EQ(0, zip_writer.WriteBytes(entry.second.data(), entry.second.size()));
@@ -93,6 +99,37 @@
   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) {
+  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.c_str(), kNoCause, &updater_info);
+
+  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
+  CloseArchive(handle);
+}
+
 static std::string get_sha1(const std::string& content) {
   uint8_t digest[SHA_DIGEST_LENGTH];
   SHA1(reinterpret_cast<const uint8_t*>(content.c_str()), content.size(), digest);
@@ -101,19 +138,39 @@
 
 class UpdaterTest : public ::testing::Test {
  protected:
-  virtual void SetUp() override {
+  void SetUp() override {
     RegisterBuiltins();
     RegisterInstallFunctions();
     RegisterBlockImageFunctions();
 
+    // 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);
+
+    last_command_file_ = temp_last_command_.path;
+    image_file_ = image_temp_file_.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 += "/" + get_sha1(image_temp_file_.path) + ".UPDATED";
+    ASSERT_TRUE(android::base::RemoveFileIfExists(updated_marker));
   }
 
   TemporaryFile temp_saved_source_;
-  TemporaryFile temp_last_command_;
   TemporaryDir temp_stash_base_;
+  std::string last_command_file_;
+  std::string image_file_;
+
+ private:
+  TemporaryFile temp_last_command_;
+  TemporaryFile image_temp_file_;
 };
 
 TEST_F(UpdaterTest, getprop) {
@@ -453,16 +510,18 @@
 
   // Generate the patch data.
   TemporaryFile patch_file;
-  ASSERT_EQ(0, bsdiff::bsdiff(reinterpret_cast<const uint8_t*>(src_content.data()),
-      src_content.size(), reinterpret_cast<const uint8_t*>(tgt_content.data()),
-      tgt_content.size(), patch_file.path, nullptr));
+  ASSERT_EQ(0,
+            bsdiff::bsdiff(reinterpret_cast<const uint8_t*>(src_content.data()), src_content.size(),
+                           reinterpret_cast<const uint8_t*>(tgt_content.data()), tgt_content.size(),
+                           patch_file.path, nullptr));
   std::string patch_content;
   ASSERT_TRUE(android::base::ReadFileToString(patch_file.path, &patch_content));
 
   // Create the transfer list that contains a bsdiff.
   std::string src_hash = get_sha1(src_content);
   std::string tgt_hash = get_sha1(tgt_content);
-  std::vector<std::string> transfer_list = {
+  std::vector<std::string> transfer_list{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -471,183 +530,108 @@
     android::base::StringPrintf("bsdiff 0 %zu %s %s 2,0,2 2 - %s:2,0,2", patch_content.size(),
                                 src_hash.c_str(), tgt_hash.c_str(), src_hash.c_str()),
     "free " + src_hash,
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", patch_content },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  ASSERT_TRUE(android::base::WriteStringToFile(src_content, image_file_));
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 
-  // 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;
-
-  // Execute the commands in the transfer list.
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "new_data", "patch_data"))";
-  expect("t", script.c_str(), kNoCause, &updater_info);
   // The update_file should be patched correctly.
   std::string updated_content;
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_content));
-  ASSERT_EQ(tgt_hash, get_sha1(updated_content));
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_content));
+  ASSERT_EQ(tgt_content, updated_content);
 }
 
 TEST_F(UpdaterTest, block_image_update_fail) {
   std::string src_content(4096 * 2, 'e');
   std::string src_hash = get_sha1(src_content);
   // Stash and free some blocks, then fail the update intentionally.
-  std::vector<std::string> transfer_list = {
-    "4", "2", "0", "2", "stash " + src_hash + " 2,0,2", "free " + src_hash, "fail",
+  std::vector<std::string> transfer_list{
+    // clang-format off
+    "4",
+    "2",
+    "0",
+    "2",
+    "stash " + src_hash + " 2,0,2",
+    "free " + src_hash,
+    "fail",
+    // clang-format on
   };
 
   // Add a new data of 10 bytes to test the deadlock.
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", std::string(10, 0) },
     { "patch_data", "" },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  ASSERT_TRUE(android::base::WriteStringToFile(src_content, image_file_));
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
-  // 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;
-
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  // Expect the stashed blocks to be freed.
-  std::string script = "block_image_update(\"" + std::string(update_file.path) +
-                       R"(", package_extract_file("transfer_list"), "new_data", "patch_data"))";
-  expect("", script.c_str(), kNoCause, &updater_info);
   // Updater generates the stash name based on the input file name.
-  std::string name_digest = get_sha1(update_file.path);
+  std::string name_digest = get_sha1(image_file_);
   std::string stash_base = std::string(temp_stash_base_.path) + "/" + name_digest;
   ASSERT_EQ(0, access(stash_base.c_str(), F_OK));
+  // Expect the stashed blocks to be freed.
   ASSERT_EQ(-1, access((stash_base + src_hash).c_str(), F_OK));
   ASSERT_EQ(0, rmdir(stash_base.c_str()));
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
 }
 
 TEST_F(UpdaterTest, new_data_over_write) {
-  std::vector<std::string> transfer_list = {
-    "4", "1", "0", "0", "new 2,0,1",
-  };
-
-  // Write 4096 + 100 bytes of new data.
-  std::unordered_map<std::string, std::string> entries = {
-    { "new_data", std::string(4196, 0) },
-    { "patch_data", "" },
-    { "transfer_list", android::base::Join(transfer_list, '\n') },
-  };
-
-  // 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;
-
-  TemporaryFile update_file;
-  std::string script = "block_image_update(\"" + std::string(update_file.path) +
-                       R"(", package_extract_file("transfer_list"), "new_data", "patch_data"))";
-  expect("t", script.c_str(), kNoCause, &updater_info);
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
-}
-
-TEST_F(UpdaterTest, new_data_short_write) {
-  std::vector<std::string> transfer_list = {
+  std::vector<std::string> transfer_list{
+    // clang-format off
     "4",
     "1",
     "0",
     "0",
     "new 2,0,1",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
-    { "empty_new_data", "" },
-    { "short_new_data", std::string(10, 'a') },
-    { "exact_new_data", std::string(4096, 'a') },
+  // Write 4096 + 100 bytes of new data.
+  PackageEntries entries{
+    { "new_data", std::string(4196, 0) },
     { "patch_data", "" },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  RunBlockImageUpdate(false, entries, image_file_, "t");
+}
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+TEST_F(UpdaterTest, new_data_short_write) {
+  std::vector<std::string> transfer_list{
+    // clang-format off
+    "4",
+    "1",
+    "0",
+    "0",
+    "new 2,0,1",
+    // clang-format on
+  };
 
-  // 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;
+  PackageEntries entries{
+    { "patch_data", "" },
+    { "transfer_list", android::base::Join(transfer_list, '\n') },
+  };
 
   // Updater should report the failure gracefully rather than stuck in deadlock.
-  TemporaryFile update_file;
-  std::string script_empty_data = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "empty_new_data", "patch_data"))";
-  expect("", script_empty_data.c_str(), kNoCause, &updater_info);
+  entries["new_data"] = "";
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
-  std::string script_short_data = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "short_new_data", "patch_data"))";
-  expect("", script_short_data.c_str(), kNoCause, &updater_info);
+  entries["new_data"] = std::string(10, 'a');
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
   // Expect to write 1 block of new data successfully.
-  std::string script_exact_data = "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "exact_new_data", "patch_data"))";
-  expect("t", script_exact_data.c_str(), kNoCause, &updater_info);
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  entries["new_data"] = std::string(4096, 'a');
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 }
 
 TEST_F(UpdaterTest, brotli_new_data) {
@@ -680,55 +664,30 @@
     "new 2,99,100",
   };
 
-  std::unordered_map<std::string, std::string> entries = {
-    { "new.dat.br", std::move(encoded_data) },
+  PackageEntries entries{
+    { "new_data.br", std::move(encoded_data) },
     { "patch_data", "" },
     { "transfer_list", android::base::Join(transfer_list, '\n') },
   };
 
-  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(), "wb");
-  updater_info.package_zip_addr = map.addr;
-  updater_info.package_zip_len = map.length;
-
-  // Check if we can decompress the new data correctly.
-  TemporaryFile update_file;
-  std::string script_new_data =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list"), "new.dat.br", "patch_data"))";
-  expect("t", script_new_data.c_str(), kNoCause, &updater_info);
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 
   std::string updated_content;
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_content));
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_content));
   ASSERT_EQ(brotli_new_data, updated_content);
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
 }
 
 TEST_F(UpdaterTest, last_command_update) {
-  std::string last_command_file = Paths::Get().last_command_file();
-
-  std::string block1 = std::string(4096, '1');
-  std::string block2 = std::string(4096, '2');
-  std::string block3 = std::string(4096, '3');
+  std::string block1(4096, '1');
+  std::string block2(4096, '2');
+  std::string block3(4096, '3');
   std::string block1_hash = get_sha1(block1);
   std::string block2_hash = get_sha1(block2);
   std::string block3_hash = get_sha1(block3);
 
   // Compose the transfer list to fail the first update.
-  std::vector<std::string> transfer_list_fail = {
+  std::vector<std::string> transfer_list_fail{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -737,10 +696,12 @@
     "move " + block1_hash + " 2,1,2 1 2,0,1",
     "stash " + block3_hash + " 2,2,3",
     "fail",
+    // clang-format on
   };
 
   // Mimic a resumed update with the same transfer commands.
-  std::vector<std::string> transfer_list_continue = {
+  std::vector<std::string> transfer_list_continue{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -749,127 +710,86 @@
     "move " + block1_hash + " 2,1,2 1 2,0,1",
     "stash " + block3_hash + " 2,2,3",
     "move " + block1_hash + " 2,2,3 1 2,0,1",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block2 + block3, image_file_));
+
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", "" },
-    { "transfer_list_fail", android::base::Join(transfer_list_fail, '\n') },
-    { "transfer_list_continue", android::base::Join(transfer_list_continue, '\n') },
+    { "transfer_list", android::base::Join(transfer_list_fail, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  // "2\nstash " + block3_hash + " 2,2,3"
+  std::string last_command_content = "2\n" + transfer_list_fail[kTransferListHeaderLines + 2];
 
-  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 src_content = block1 + block2 + block3;
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_fail"), "new_data", "patch_data"))";
-  expect("", script.c_str(), kNoCause, &updater_info);
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
   // Expect last_command to contain the last stash command.
-  std::string last_command_content;
-  ASSERT_TRUE(android::base::ReadFileToString(last_command_file.c_str(), &last_command_content));
-  EXPECT_EQ("2\nstash " + block3_hash + " 2,2,3", last_command_content);
+  std::string last_command_actual;
+  ASSERT_TRUE(android::base::ReadFileToString(last_command_file_, &last_command_actual));
+  EXPECT_EQ(last_command_content, last_command_actual);
+
   std::string updated_contents;
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_contents));
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_contents));
   ASSERT_EQ(block1 + block1 + block3, updated_contents);
 
-  // Resume the update, expect the first 'move' to be skipped but the second 'move' to be executed.
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script_second_update =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_continue"), "new_data", "patch_data"))";
-  expect("t", script_second_update.c_str(), kNoCause, &updater_info);
-  ASSERT_TRUE(android::base::ReadFileToString(update_file.path, &updated_contents));
-  ASSERT_EQ(block1 + block2 + block1, updated_contents);
+  // "Resume" the update. Expect the first 'move' to be skipped but the second 'move' to be
+  // executed. Note that we intentionally reset the image file.
+  entries["transfer_list"] = android::base::Join(transfer_list_continue, '\n');
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block2 + block3, image_file_));
+  RunBlockImageUpdate(false, entries, image_file_, "t");
 
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  ASSERT_TRUE(android::base::ReadFileToString(image_file_, &updated_contents));
+  ASSERT_EQ(block1 + block2 + block1, updated_contents);
 }
 
 TEST_F(UpdaterTest, last_command_update_unresumable) {
-  std::string last_command_file = Paths::Get().last_command_file();
-
-  std::string block1 = std::string(4096, '1');
-  std::string block2 = std::string(4096, '2');
+  std::string block1(4096, '1');
+  std::string block2(4096, '2');
   std::string block1_hash = get_sha1(block1);
   std::string block2_hash = get_sha1(block2);
 
   // Construct an unresumable update with source blocks mismatch.
-  std::vector<std::string> transfer_list_unresumable = {
-    "4", "2", "0", "2", "stash " + block1_hash + " 2,0,1", "move " + block2_hash + " 2,1,2 1 2,0,1",
+  std::vector<std::string> transfer_list_unresumable{
+    // clang-format off
+    "4",
+    "2",
+    "0",
+    "2",
+    "stash " + block1_hash + " 2,0,1",
+    "move " + block2_hash + " 2,1,2 1 2,0,1",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", "" },
-    { "transfer_list_unresumable", android::base::Join(transfer_list_unresumable, '\n') },
+    { "transfer_list", android::base::Join(transfer_list_unresumable, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block1, image_file_));
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+  std::string last_command_content = "0\n" + transfer_list_unresumable[kTransferListHeaderLines];
+  ASSERT_TRUE(android::base::WriteStringToFile(last_command_content, last_command_file_));
 
-  // 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;
+  RunBlockImageUpdate(false, entries, image_file_, "");
 
-  // Set up the last_command_file
-  ASSERT_TRUE(
-      android::base::WriteStringToFile("0\nstash " + block1_hash + " 2,0,1", last_command_file));
-
-  // The last_command_file will be deleted if the update encounters an unresumable failure
-  // later.
-  std::string src_content = block1 + block1;
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  std::string script =
-      "block_image_update(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_unresumable"), "new_data", "patch_data"))";
-  expect("", script.c_str(), kNoCause, &updater_info);
-  ASSERT_EQ(-1, access(last_command_file.c_str(), R_OK));
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  // The last_command_file will be deleted if the update encounters an unresumable failure later.
+  ASSERT_EQ(-1, access(last_command_file_.c_str(), R_OK));
 }
 
 TEST_F(UpdaterTest, last_command_verify) {
-  std::string last_command_file = Paths::Get().last_command_file();
-
-  std::string block1 = std::string(4096, '1');
-  std::string block2 = std::string(4096, '2');
-  std::string block3 = std::string(4096, '3');
+  std::string block1(4096, '1');
+  std::string block2(4096, '2');
+  std::string block3(4096, '3');
   std::string block1_hash = get_sha1(block1);
   std::string block2_hash = get_sha1(block2);
   std::string block3_hash = get_sha1(block3);
 
-  std::vector<std::string> transfer_list_verify = {
+  std::vector<std::string> transfer_list_verify{
+    // clang-format off
     "4",
     "2",
     "0",
@@ -878,55 +798,33 @@
     "move " + block1_hash + " 2,0,1 1 2,0,1",
     "move " + block1_hash + " 2,1,2 1 2,0,1",
     "stash " + block3_hash + " 2,2,3",
+    // clang-format on
   };
 
-  std::unordered_map<std::string, std::string> entries = {
+  PackageEntries entries{
     { "new_data", "" },
     { "patch_data", "" },
-    { "transfer_list_verify", android::base::Join(transfer_list_verify, '\n') },
+    { "transfer_list", android::base::Join(transfer_list_verify, '\n') },
   };
 
-  // Build the update package.
-  TemporaryFile zip_file;
-  BuildUpdatePackage(entries, zip_file.release());
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block1 + block3, image_file_));
 
-  MemMapping map;
-  ASSERT_TRUE(map.MapFile(zip_file.path));
-  ZipArchiveHandle handle;
-  ASSERT_EQ(0, OpenArchiveFromMemory(map.addr, map.length, zip_file.path, &handle));
+  // Last command: "move " + block1_hash + " 2,1,2 1 2,0,1"
+  std::string last_command_content = "2\n" + transfer_list_verify[kTransferListHeaderLines + 2];
 
-  // 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;
+  // First run: expect the verification to succeed and the last_command_file is intact.
+  ASSERT_TRUE(android::base::WriteStringToFile(last_command_content, last_command_file_));
 
-  std::string src_content = block1 + block1 + block3;
-  TemporaryFile update_file;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
+  RunBlockImageUpdate(true, entries, image_file_, "t");
 
-  ASSERT_TRUE(
-      android::base::WriteStringToFile("2\nstash " + block3_hash + " 2,2,3", last_command_file));
+  std::string last_command_actual;
+  ASSERT_TRUE(android::base::ReadFileToString(last_command_file_, &last_command_actual));
+  EXPECT_EQ(last_command_content, last_command_actual);
 
-  // Expect the verification to succeed and the last_command_file is intact.
-  std::string script_verify =
-      "block_image_verify(\"" + std::string(update_file.path) +
-      R"(", package_extract_file("transfer_list_verify"), "new_data","patch_data"))";
-  expect("t", script_verify.c_str(), kNoCause, &updater_info);
-
-  std::string last_command_content;
-  ASSERT_TRUE(android::base::ReadFileToString(last_command_file.c_str(), &last_command_content));
-  EXPECT_EQ("2\nstash " + block3_hash + " 2,2,3", last_command_content);
-
-  // Expect the verification to succeed but last_command_file to be deleted; because the target
-  // blocks don't have the expected contents for the second move command.
-  src_content = block1 + block2 + block3;
-  ASSERT_TRUE(android::base::WriteStringToFile(src_content, update_file.path));
-  expect("t", script_verify.c_str(), kNoCause, &updater_info);
-  ASSERT_EQ(-1, access(last_command_file.c_str(), R_OK));
-
-  ASSERT_EQ(0, fclose(updater_info.cmd_pipe));
-  CloseArchive(handle);
+  // Second run with a mismatching block image: expect the verification to succeed but
+  // last_command_file to be deleted; because the target blocks in the last command don't have the
+  // expected contents for the second move command.
+  ASSERT_TRUE(android::base::WriteStringToFile(block1 + block2 + block3, image_file_));
+  RunBlockImageUpdate(true, entries, image_file_, "t");
+  ASSERT_EQ(-1, access(last_command_file_.c_str(), R_OK));
 }
diff --git a/tests/testdata/gzipped_source b/tests/testdata/gzipped_source
new file mode 100644
index 0000000..6d425d0
--- /dev/null
+++ b/tests/testdata/gzipped_source
Binary files differ
diff --git a/tests/testdata/gzipped_target b/tests/testdata/gzipped_target
new file mode 100644
index 0000000..5621262
--- /dev/null
+++ b/tests/testdata/gzipped_target
Binary files differ
diff --git a/tests/unit/commands_test.cpp b/tests/unit/commands_test.cpp
new file mode 100644
index 0000000..18aa471
--- /dev/null
+++ b/tests/unit/commands_test.cpp
@@ -0,0 +1,37 @@
+/*
+ * 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 <string>
+
+#include <gtest/gtest.h>
+
+#include "private/commands.h"
+
+TEST(CommandsTest, ParseType) {
+  ASSERT_EQ(Command::Type::ZERO, Command::ParseType("zero"));
+  ASSERT_EQ(Command::Type::NEW, Command::ParseType("new"));
+  ASSERT_EQ(Command::Type::ERASE, Command::ParseType("erase"));
+  ASSERT_EQ(Command::Type::MOVE, Command::ParseType("move"));
+  ASSERT_EQ(Command::Type::BSDIFF, Command::ParseType("bsdiff"));
+  ASSERT_EQ(Command::Type::IMGDIFF, Command::ParseType("imgdiff"));
+  ASSERT_EQ(Command::Type::STASH, Command::ParseType("stash"));
+  ASSERT_EQ(Command::Type::FREE, Command::ParseType("free"));
+}
+
+TEST(CommandsTest, ParseType_InvalidCommand) {
+  ASSERT_EQ(Command::Type::LAST, Command::ParseType("foo"));
+  ASSERT_EQ(Command::Type::LAST, Command::ParseType("bar"));
+}
diff --git a/tools/Android.mk b/tools/Android.mk
deleted file mode 100644
index 6571161..0000000
--- a/tools/Android.mk
+++ /dev/null
@@ -1 +0,0 @@
-include $(all-subdir-makefiles)
diff --git a/tools/dumpkey/Android.bp b/tools/dumpkey/Android.bp
new file mode 100644
index 0000000..eb45e31
--- /dev/null
+++ b/tools/dumpkey/Android.bp
@@ -0,0 +1,27 @@
+// 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.
+
+java_library_host {
+    name: "dumpkey",
+
+    manifest: "DumpPublicKey.mf",
+
+    srcs: [
+        "DumpPublicKey.java",
+    ],
+
+    static_libs: [
+        "bouncycastle-host",
+    ],
+}
diff --git a/tools/dumpkey/Android.mk b/tools/dumpkey/Android.mk
deleted file mode 100644
index 3154914..0000000
--- a/tools/dumpkey/Android.mk
+++ /dev/null
@@ -1,22 +0,0 @@
-# Copyright (C) 2008 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.
-
-LOCAL_PATH := $(call my-dir)
-
-include $(CLEAR_VARS)
-LOCAL_MODULE := dumpkey
-LOCAL_SRC_FILES := DumpPublicKey.java
-LOCAL_JAR_MANIFEST := DumpPublicKey.mf
-LOCAL_STATIC_JAVA_LIBRARIES := bouncycastle-host
-include $(BUILD_HOST_JAVA_LIBRARY)
diff --git a/tools/recovery_l10n/Android.bp b/tools/recovery_l10n/Android.bp
new file mode 100644
index 0000000..d0a6d4b
--- /dev/null
+++ b/tools/recovery_l10n/Android.bp
@@ -0,0 +1,23 @@
+// 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.
+
+android_app {
+    name: "RecoveryLocalizer",
+
+    sdk_version: "current",
+
+    srcs: [
+        "src/**/*.java",
+    ],
+}
diff --git a/tools/recovery_l10n/Android.mk b/tools/recovery_l10n/Android.mk
deleted file mode 100644
index 7197c5c..0000000
--- a/tools/recovery_l10n/Android.mk
+++ /dev/null
@@ -1,13 +0,0 @@
-# Copyright 2012 Google Inc. All Rights Reserved.
-
-LOCAL_PATH := $(call my-dir)
-
-include $(CLEAR_VARS)
-
-LOCAL_PACKAGE_NAME := RecoveryLocalizer
-LOCAL_SDK_VERSION := current
-LOCAL_MODULE_TAGS := optional
-
-LOCAL_SRC_FILES := $(call all-java-files-under, src)
-
-include $(BUILD_PACKAGE)
diff --git a/updater/Android.mk b/updater/Android.mk
index 4762664..46c56f4 100644
--- a/updater/Android.mk
+++ b/updater/Android.mk
@@ -56,6 +56,7 @@
 LOCAL_MODULE := libupdater
 
 LOCAL_SRC_FILES := \
+    commands.cpp \
     install.cpp \
     blockimg.cpp
 
diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index 236644e..5d6da6c 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -57,6 +57,7 @@
 #include "otautil/paths.h"
 #include "otautil/print_sha1.h"
 #include "otautil/rangeset.h"
+#include "private/commands.h"
 #include "updater/install.h"
 #include "updater/updater.h"
 
@@ -82,7 +83,7 @@
 
 // Parse the last command index of the last update and save the result to |last_command_index|.
 // Return true if we successfully read the index.
-static bool ParseLastCommandFile(int* last_command_index) {
+static bool ParseLastCommandFile(size_t* last_command_index) {
   const std::string& last_command_file = Paths::Get().last_command_file();
   android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(last_command_file.c_str(), O_RDONLY)));
   if (fd == -1) {
@@ -133,7 +134,7 @@
 }
 
 // Update the last executed command index in the last_command_file.
-static bool UpdateLastCommandIndex(int command_index, const std::string& command_string) {
+static bool UpdateLastCommandIndex(size_t command_index, const std::string& command_string) {
   const std::string& last_command_file = Paths::Get().last_command_file();
   std::string last_command_tmp = last_command_file + ".tmp";
   std::string content = std::to_string(command_index) + "\n" + command_string;
@@ -546,9 +547,8 @@
 struct CommandParameters {
     std::vector<std::string> tokens;
     size_t cpos;
-    int cmdindex;
-    const char* cmdname;
-    const char* cmdline;
+    std::string cmdname;
+    std::string cmdline;
     std::string freestash;
     std::string stashbase;
     bool canwrite;
@@ -1497,23 +1497,13 @@
   return 0;
 }
 
-// Definitions for transfer list command functions
-typedef int (*CommandFunction)(CommandParameters&);
+using CommandFunction = std::function<int(CommandParameters&)>;
 
-struct Command {
-    const char* name;
-    CommandFunction f;
-};
-
-// args:
-//    - block device (or file) to modify in-place
-//    - transfer list (blob)
-//    - new data stream (filename within package.zip)
-//    - patch stream (filename within package.zip, must be uncompressed)
+using CommandMap = std::unordered_map<Command::Type, CommandFunction>;
 
 static Value* PerformBlockImageUpdate(const char* name, State* state,
                                       const std::vector<std::unique_ptr<Expr>>& argv,
-                                      const Command* commands, size_t cmdcount, bool dryrun) {
+                                      const CommandMap& command_map, bool dryrun) {
   CommandParameters params = {};
   params.canwrite = !dryrun;
 
@@ -1533,6 +1523,11 @@
     return nullptr;
   }
 
+  // args:
+  //   - block device (or file) to modify in-place
+  //   - transfer list (blob)
+  //   - new data stream (filename within package.zip)
+  //   - patch stream (filename within package.zip, must be uncompressed)
   const std::unique_ptr<Value>& blockdev_filename = args[0];
   const std::unique_ptr<Value>& transfer_list_value = args[1];
   const std::unique_ptr<Value>& new_data_fn = args[2];
@@ -1666,7 +1661,6 @@
     return StringValue("t");
   }
 
-  size_t start = 2;
   if (lines.size() < 4) {
     ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zu]",
                lines.size());
@@ -1691,8 +1685,8 @@
 
   params.createdstash = res;
 
-  // When performing an update, save the index and cmdline of the current command into
-  // the last_command_file.
+  // When performing an update, save the index and cmdline of the current command into the
+  // last_command_file.
   // Upon resuming an update, read the saved index first; then
   //   1. In verification mode, check if the 'move' or 'diff' commands before the saved index has
   //      the expected target blocks already. If not, these commands cannot be skipped and we need
@@ -1701,87 +1695,73 @@
   //   2. In update mode, skip all commands before the saved index. Therefore, we can avoid deleting
   //      stashes with duplicate id unintentionally (b/69858743); and also speed up the update.
   // If an update succeeds or is unresumable, delete the last_command_file.
-  int saved_last_command_index;
+  bool skip_executed_command = true;
+  size_t saved_last_command_index;
   if (!ParseLastCommandFile(&saved_last_command_index)) {
     DeleteLastCommandFile();
-    // We failed to parse the last command, set it explicitly to -1.
-    saved_last_command_index = -1;
-  }
-
-  start += 2;
-
-  // Build a map of the available commands
-  std::unordered_map<std::string, const Command*> cmd_map;
-  for (size_t i = 0; i < cmdcount; ++i) {
-    if (cmd_map.find(commands[i].name) != cmd_map.end()) {
-      LOG(ERROR) << "Error: command [" << commands[i].name << "] already exists in the cmd map.";
-      return StringValue("");
-    }
-    cmd_map[commands[i].name] = &commands[i];
+    // We failed to parse the last command. Disallow skipping executed commands.
+    skip_executed_command = false;
   }
 
   int rc = -1;
 
+  static constexpr size_t kTransferListHeaderLines = 4;
   // Subsequent lines are all individual transfer commands
-  for (size_t i = start; i < lines.size(); i++) {
+  for (size_t i = kTransferListHeaderLines; i < lines.size(); i++) {
     const std::string& line = lines[i];
     if (line.empty()) continue;
 
+    size_t cmdindex = i - kTransferListHeaderLines;
     params.tokens = android::base::Split(line, " ");
     params.cpos = 0;
-    if (i - start > std::numeric_limits<int>::max()) {
-      params.cmdindex = -1;
-    } else {
-      params.cmdindex = i - start;
-    }
-    params.cmdname = params.tokens[params.cpos++].c_str();
-    params.cmdline = line.c_str();
+    params.cmdname = params.tokens[params.cpos++];
+    params.cmdline = line;
     params.target_verified = false;
 
-    if (cmd_map.find(params.cmdname) == cmd_map.end()) {
+    Command::Type cmd_type = Command::ParseType(params.cmdname);
+    if (cmd_type == Command::Type::LAST) {
       LOG(ERROR) << "unexpected command [" << params.cmdname << "]";
       goto pbiudone;
     }
 
-    const Command* cmd = cmd_map[params.cmdname];
+    const CommandFunction& performer = command_map.at(cmd_type);
 
     // Skip the command if we explicitly set the corresponding function pointer to nullptr, e.g.
     // "erase" during block_image_verify.
-    if (cmd->f == nullptr) {
+    if (performer == nullptr) {
       LOG(DEBUG) << "skip executing command [" << line << "]";
       continue;
     }
 
-    std::string cmdname = std::string(params.cmdname);
-
     // Skip all commands before the saved last command index when resuming an update, except for
     // "new" command. Because new commands read in the data sequentially.
-    if (params.canwrite && params.cmdindex != -1 && params.cmdindex <= saved_last_command_index &&
-        cmdname != "new") {
-      LOG(INFO) << "Skipping already executed command: " << params.cmdindex
+    if (params.canwrite && skip_executed_command && cmdindex <= saved_last_command_index &&
+        cmd_type != Command::Type::NEW) {
+      LOG(INFO) << "Skipping already executed command: " << cmdindex
                 << ", last executed command for previous update: " << saved_last_command_index;
       continue;
     }
 
-    if (cmd->f(params) == -1) {
+    if (performer(params) == -1) {
       LOG(ERROR) << "failed to execute command [" << line << "]";
       goto pbiudone;
     }
 
-    // In verify mode, check if the commands before the saved last_command_index have been
-    // executed correctly. If some target blocks have unexpected contents, delete the last command
-    // file so that we will resume the update from the first command in the transfer list.
-    if (!params.canwrite && saved_last_command_index != -1 && params.cmdindex != -1 &&
-        params.cmdindex <= saved_last_command_index) {
+    // In verify mode, check if the commands before the saved last_command_index have been executed
+    // correctly. If some target blocks have unexpected contents, delete the last command file so
+    // that we will resume the update from the first command in the transfer list.
+    if (!params.canwrite && skip_executed_command && cmdindex <= saved_last_command_index) {
       // TODO(xunchang) check that the cmdline of the saved index is correct.
-      if ((cmdname == "move" || cmdname == "bsdiff" || cmdname == "imgdiff") &&
+      if ((cmd_type == Command::Type::MOVE || cmd_type == Command::Type::BSDIFF ||
+           cmd_type == Command::Type::IMGDIFF) &&
           !params.target_verified) {
         LOG(WARNING) << "Previously executed command " << saved_last_command_index << ": "
                      << params.cmdline << " doesn't produce expected target blocks.";
-        saved_last_command_index = -1;
+        skip_executed_command = false;
         DeleteLastCommandFile();
       }
     }
+
     if (params.canwrite) {
       if (ota_fsync(params.fd) == -1) {
         failure_type = kFsyncFailure;
@@ -1789,7 +1769,7 @@
         goto pbiudone;
       }
 
-      if (!UpdateLastCommandIndex(params.cmdindex, params.cmdline)) {
+      if (!UpdateLastCommandIndex(cmdindex, params.cmdline)) {
         LOG(WARNING) << "Failed to update the last command file.";
       }
 
@@ -1918,38 +1898,42 @@
  */
 Value* BlockImageVerifyFn(const char* name, State* state,
                           const std::vector<std::unique_ptr<Expr>>& argv) {
-    // Commands which are not tested are set to nullptr to skip them completely
-    const Command commands[] = {
-        { "bsdiff",     PerformCommandDiff  },
-        { "erase",      nullptr             },
-        { "free",       PerformCommandFree  },
-        { "imgdiff",    PerformCommandDiff  },
-        { "move",       PerformCommandMove  },
-        { "new",        nullptr             },
-        { "stash",      PerformCommandStash },
-        { "zero",       nullptr             }
-    };
+  // Commands which are not allowed are set to nullptr to skip them completely.
+  const CommandMap command_map{
+    // clang-format off
+    { Command::Type::BSDIFF,  PerformCommandDiff },
+    { Command::Type::ERASE,   nullptr },
+    { Command::Type::FREE,    PerformCommandFree },
+    { Command::Type::IMGDIFF, PerformCommandDiff },
+    { Command::Type::MOVE,    PerformCommandMove },
+    { Command::Type::NEW,     nullptr },
+    { Command::Type::STASH,   PerformCommandStash },
+    { Command::Type::ZERO,    nullptr },
+    // clang-format on
+  };
+  CHECK_EQ(static_cast<size_t>(Command::Type::LAST), command_map.size());
 
-    // Perform a dry run without writing to test if an update can proceed
-    return PerformBlockImageUpdate(name, state, argv, commands,
-                sizeof(commands) / sizeof(commands[0]), true);
+  // Perform a dry run without writing to test if an update can proceed.
+  return PerformBlockImageUpdate(name, state, argv, command_map, true);
 }
 
 Value* BlockImageUpdateFn(const char* name, State* state,
                           const std::vector<std::unique_ptr<Expr>>& argv) {
-    const Command commands[] = {
-        { "bsdiff",     PerformCommandDiff  },
-        { "erase",      PerformCommandErase },
-        { "free",       PerformCommandFree  },
-        { "imgdiff",    PerformCommandDiff  },
-        { "move",       PerformCommandMove  },
-        { "new",        PerformCommandNew   },
-        { "stash",      PerformCommandStash },
-        { "zero",       PerformCommandZero  }
-    };
+  const CommandMap command_map{
+    // clang-format off
+    { Command::Type::BSDIFF,  PerformCommandDiff },
+    { Command::Type::ERASE,   PerformCommandErase },
+    { Command::Type::FREE,    PerformCommandFree },
+    { Command::Type::IMGDIFF, PerformCommandDiff },
+    { Command::Type::MOVE,    PerformCommandMove },
+    { Command::Type::NEW,     PerformCommandNew },
+    { Command::Type::STASH,   PerformCommandStash },
+    { Command::Type::ZERO,    PerformCommandZero },
+    // clang-format on
+  };
+  CHECK_EQ(static_cast<size_t>(Command::Type::LAST), command_map.size());
 
-    return PerformBlockImageUpdate(name, state, argv, commands,
-                sizeof(commands) / sizeof(commands[0]), false);
+  return PerformBlockImageUpdate(name, state, argv, command_map, false);
 }
 
 Value* RangeSha1Fn(const char* name, State* state, const std::vector<std::unique_ptr<Expr>>& argv) {
diff --git a/updater/commands.cpp b/updater/commands.cpp
new file mode 100644
index 0000000..f798c6a
--- /dev/null
+++ b/updater/commands.cpp
@@ -0,0 +1,43 @@
+/*
+ * 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 "private/commands.h"
+
+#include <string>
+
+#include <android-base/logging.h>
+
+Command::Type Command::ParseType(const std::string& type_str) {
+  if (type_str == "zero") {
+    return Type::ZERO;
+  } else if (type_str == "new") {
+    return Type::NEW;
+  } else if (type_str == "erase") {
+    return Type::ERASE;
+  } else if (type_str == "move") {
+    return Type::MOVE;
+  } else if (type_str == "bsdiff") {
+    return Type::BSDIFF;
+  } else if (type_str == "imgdiff") {
+    return Type::IMGDIFF;
+  } else if (type_str == "stash") {
+    return Type::STASH;
+  } else if (type_str == "free") {
+    return Type::FREE;
+  }
+  LOG(ERROR) << "Invalid type: " << type_str;
+  return Type::LAST;
+};
diff --git a/updater/include/private/commands.h b/updater/include/private/commands.h
new file mode 100644
index 0000000..b360000
--- /dev/null
+++ b/updater/include/private/commands.h
@@ -0,0 +1,35 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <string>
+
+struct Command {
+  enum class Type {
+    ZERO,
+    NEW,
+    ERASE,
+    MOVE,
+    BSDIFF,
+    IMGDIFF,
+    STASH,
+    FREE,
+    LAST,  // Not a valid type.
+  };
+
+  static Type ParseType(const std::string& type_str);
+};
diff --git a/updater_sample/OWNERS b/updater_sample/OWNERS
new file mode 100644
index 0000000..5c1c370
--- /dev/null
+++ b/updater_sample/OWNERS
@@ -0,0 +1,2 @@
+zhaojiac@google.com
+zhomart@google.com
diff --git a/updater_sample/README.md b/updater_sample/README.md
index c68c07c..3f211dd 100644
--- a/updater_sample/README.md
+++ b/updater_sample/README.md
@@ -90,9 +90,9 @@
 - [x] Add demo for passing HTTP headers to `UpdateEngine#applyPayload`
 - [x] [Package compatibility check](https://source.android.com/devices/architecture/vintf/match-rules)
 - [x] Deferred switch slot demo
-- [ ] Add tests for `MainActivity`
+- [ ] Add demo for passing NETWORK_ID to `UpdateEngine#applyPayload`
 - [ ] Verify system partition checksum for package
-- [ ] Add non-A/B updates demo
+- [?] Add non-A/B updates demo
 
 
 ## Running tests
diff --git a/updater_sample/res/layout/activity_main.xml b/updater_sample/res/layout/activity_main.xml
index d9e56b4..7cde42c 100644
--- a/updater_sample/res/layout/activity_main.xml
+++ b/updater_sample/res/layout/activity_main.xml
@@ -111,19 +111,38 @@
                 android:orientation="horizontal">
 
                 <TextView
-                    android:id="@+id/textView"
+                    android:id="@+id/textView3"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
-                    android:text="Update status:" />
+                    android:text="Updater state:" />
 
                 <TextView
-                    android:id="@+id/textViewStatus"
+                    android:id="@+id/textViewUpdaterState"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
                     android:layout_marginLeft="8dp"
                     android:text="@string/unknown" />
             </LinearLayout>
 
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="4dp"
+                android:orientation="horizontal">
+
+                <TextView
+                    android:id="@+id/textView"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="Engine status:" />
+
+                <TextView
+                    android:id="@+id/textViewEngineStatus"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:layout_marginLeft="8dp"
+                    android:text="@string/unknown" />
+            </LinearLayout>
 
             <LinearLayout
                 android:layout_width="match_parent"
@@ -135,10 +154,10 @@
                     android:id="@+id/textView2"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
-                    android:text="Update completion:" />
+                    android:text="Engine error:" />
 
                 <TextView
-                    android:id="@+id/textViewCompletion"
+                    android:id="@+id/textViewEngineErrorCode"
                     android:layout_width="wrap_content"
                     android:layout_height="wrap_content"
                     android:layout_marginLeft="8dp"
diff --git a/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java b/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
index db99f7c..1e0fadc 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/UpdateConfig.java
@@ -279,4 +279,4 @@
 
     }
 
-}
\ No newline at end of file
+}
diff --git a/updater_sample/src/com/example/android/systemupdatersample/UpdateManager.java b/updater_sample/src/com/example/android/systemupdatersample/UpdateManager.java
new file mode 100644
index 0000000..c370a4e
--- /dev/null
+++ b/updater_sample/src/com/example/android/systemupdatersample/UpdateManager.java
@@ -0,0 +1,394 @@
+/*
+ * 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.
+ */
+
+package com.example.android.systemupdatersample;
+
+import android.content.Context;
+import android.os.UpdateEngine;
+import android.os.UpdateEngineCallback;
+import android.util.Log;
+
+import com.example.android.systemupdatersample.services.PrepareStreamingService;
+import com.example.android.systemupdatersample.util.PayloadSpecs;
+import com.example.android.systemupdatersample.util.UpdateEngineErrorCodes;
+import com.example.android.systemupdatersample.util.UpdateEngineProperties;
+import com.example.android.systemupdatersample.util.UpdaterStates;
+import com.google.common.util.concurrent.AtomicDouble;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.DoubleConsumer;
+import java.util.function.IntConsumer;
+
+/**
+ * Manages the update flow. It has its own state (in memory), separate from
+ * {@link UpdateEngine}'s state. Asynchronously interacts with the {@link UpdateEngine}.
+ */
+public class UpdateManager {
+
+    private static final String TAG = "UpdateManager";
+
+    /** HTTP Header: User-Agent; it will be sent to the server when streaming the payload. */
+    private static final String HTTP_USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
+            + "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36";
+
+    private final UpdateEngine mUpdateEngine;
+    private final PayloadSpecs mPayloadSpecs;
+
+    private AtomicInteger mUpdateEngineStatus =
+            new AtomicInteger(UpdateEngine.UpdateStatusConstants.IDLE);
+    private AtomicInteger mEngineErrorCode = new AtomicInteger(UpdateEngineErrorCodes.UNKNOWN);
+    private AtomicDouble mProgress = new AtomicDouble(0);
+
+    private AtomicInteger mState = new AtomicInteger(UpdaterStates.IDLE);
+
+    private final UpdateManager.UpdateEngineCallbackImpl
+            mUpdateEngineCallback = new UpdateManager.UpdateEngineCallbackImpl();
+
+    private PayloadSpec mLastPayloadSpec;
+    private AtomicBoolean mManualSwitchSlotRequired = new AtomicBoolean(true);
+
+    private IntConsumer mOnStateChangeCallback = null;
+    private IntConsumer mOnEngineStatusUpdateCallback = null;
+    private DoubleConsumer mOnProgressUpdateCallback = null;
+    private IntConsumer mOnEngineCompleteCallback = null;
+
+    private final Object mLock = new Object();
+
+    public UpdateManager(UpdateEngine updateEngine, PayloadSpecs payloadSpecs) {
+        this.mUpdateEngine = updateEngine;
+        this.mPayloadSpecs = payloadSpecs;
+    }
+
+    /**
+     * Binds to {@link UpdateEngine}.
+     */
+    public void bind() {
+        this.mUpdateEngine.bind(mUpdateEngineCallback);
+    }
+
+    /**
+     * Unbinds from {@link UpdateEngine}.
+     */
+    public void unbind() {
+        this.mUpdateEngine.unbind();
+    }
+
+    /**
+     * @return a number from {@code 0.0} to {@code 1.0}.
+     */
+    public float getProgress() {
+        return (float) this.mProgress.get();
+    }
+
+    /**
+     * Returns true if manual switching slot is required. Value depends on
+     * the update config {@code ab_config.force_switch_slot}.
+     */
+    public boolean isManualSwitchSlotRequired() {
+        return mManualSwitchSlotRequired.get();
+    }
+
+    /**
+     * Sets SystemUpdaterSample app state change callback. Value of {@code state} will be one
+     * of the values from {@link UpdaterStates}.
+     *
+     * @param onStateChangeCallback a callback with parameter {@code state}.
+     */
+    public void setOnStateChangeCallback(IntConsumer onStateChangeCallback) {
+        synchronized (mLock) {
+            this.mOnStateChangeCallback = onStateChangeCallback;
+        }
+    }
+
+    private Optional<IntConsumer> getOnStateChangeCallback() {
+        synchronized (mLock) {
+            return mOnStateChangeCallback == null
+                    ? Optional.empty()
+                    : Optional.of(mOnStateChangeCallback);
+        }
+    }
+
+    /**
+     * Sets update engine status update callback. Value of {@code status} will
+     * be one of the values from {@link UpdateEngine.UpdateStatusConstants}.
+     *
+     * @param onStatusUpdateCallback a callback with parameter {@code status}.
+     */
+    public void setOnEngineStatusUpdateCallback(IntConsumer onStatusUpdateCallback) {
+        synchronized (mLock) {
+            this.mOnEngineStatusUpdateCallback = onStatusUpdateCallback;
+        }
+    }
+
+    private Optional<IntConsumer> getOnEngineStatusUpdateCallback() {
+        synchronized (mLock) {
+            return mOnEngineStatusUpdateCallback == null
+                    ? Optional.empty()
+                    : Optional.of(mOnEngineStatusUpdateCallback);
+        }
+    }
+
+    /**
+     * Sets update engine payload application complete callback. Value of {@code errorCode} will
+     * be one of the values from {@link UpdateEngine.ErrorCodeConstants}.
+     *
+     * @param onComplete a callback with parameter {@code errorCode}.
+     */
+    public void setOnEngineCompleteCallback(IntConsumer onComplete) {
+        synchronized (mLock) {
+            this.mOnEngineCompleteCallback = onComplete;
+        }
+    }
+
+    private Optional<IntConsumer> getOnEngineCompleteCallback() {
+        synchronized (mLock) {
+            return mOnEngineCompleteCallback == null
+                    ? Optional.empty()
+                    : Optional.of(mOnEngineCompleteCallback);
+        }
+    }
+
+    /**
+     * Sets progress update callback. Progress is a number from {@code 0.0} to {@code 1.0}.
+     *
+     * @param onProgressCallback a callback with parameter {@code progress}.
+     */
+    public void setOnProgressUpdateCallback(DoubleConsumer onProgressCallback) {
+        synchronized (mLock) {
+            this.mOnProgressUpdateCallback = onProgressCallback;
+        }
+    }
+
+    private Optional<DoubleConsumer> getOnProgressUpdateCallback() {
+        synchronized (mLock) {
+            return mOnProgressUpdateCallback == null
+                    ? Optional.empty()
+                    : Optional.of(mOnProgressUpdateCallback);
+        }
+    }
+
+    /**
+     * Updates {@link this.mState} and if state is changed,
+     * it also notifies {@link this.mOnStateChangeCallback}.
+     */
+    private void setUpdaterState(int updaterState) {
+        int previousState = mState.get();
+        mState.set(updaterState);
+        if (previousState != updaterState) {
+            getOnStateChangeCallback().ifPresent(callback -> callback.accept(updaterState));
+        }
+    }
+
+    /**
+     * Requests update engine to stop any ongoing update. If an update has been applied,
+     * leave it as is.
+     *
+     * <p>Sometimes it's possible that the
+     * update engine would throw an error when the method is called, and the only way to
+     * handle it is to catch the exception.</p>
+     */
+    public void cancelRunningUpdate() {
+        try {
+            mUpdateEngine.cancel();
+            setUpdaterState(UpdaterStates.IDLE);
+        } catch (Exception e) {
+            Log.w(TAG, "UpdateEngine failed to stop the ongoing update", e);
+        }
+    }
+
+    /**
+     * Resets update engine to IDLE state. If an update has been applied it reverts it.
+     *
+     * <p>Sometimes it's possible that the
+     * update engine would throw an error when the method is called, and the only way to
+     * handle it is to catch the exception.</p>
+     */
+    public void resetUpdate() {
+        try {
+            mUpdateEngine.resetStatus();
+            setUpdaterState(UpdaterStates.IDLE);
+        } catch (Exception e) {
+            Log.w(TAG, "UpdateEngine failed to reset the update", e);
+        }
+    }
+
+    /**
+     * Applies the given update.
+     *
+     * <p>UpdateEngine works asynchronously. This method doesn't wait until
+     * end of the update.</p>
+     */
+    public void applyUpdate(Context context, UpdateConfig config) {
+        mEngineErrorCode.set(UpdateEngineErrorCodes.UNKNOWN);
+        setUpdaterState(UpdaterStates.RUNNING);
+
+        if (!config.getAbConfig().getForceSwitchSlot()) {
+            mManualSwitchSlotRequired.set(true);
+        } else {
+            mManualSwitchSlotRequired.set(false);
+        }
+
+        if (config.getInstallType() == UpdateConfig.AB_INSTALL_TYPE_NON_STREAMING) {
+            applyAbNonStreamingUpdate(config);
+        } else {
+            applyAbStreamingUpdate(context, config);
+        }
+    }
+
+    private void applyAbNonStreamingUpdate(UpdateConfig config) {
+        List<String> extraProperties = prepareExtraProperties(config);
+
+        PayloadSpec payload;
+        try {
+            payload = mPayloadSpecs.forNonStreaming(config.getUpdatePackageFile());
+        } catch (IOException e) {
+            Log.e(TAG, "Error creating payload spec", e);
+            setUpdaterState(UpdaterStates.ERROR);
+            return;
+        }
+        updateEngineApplyPayload(payload, extraProperties);
+    }
+
+    private void applyAbStreamingUpdate(Context context, UpdateConfig config) {
+        List<String> extraProperties = prepareExtraProperties(config);
+
+        Log.d(TAG, "Starting PrepareStreamingService");
+        PrepareStreamingService.startService(context, config, (code, payloadSpec) -> {
+            if (code == PrepareStreamingService.RESULT_CODE_SUCCESS) {
+                extraProperties.add("USER_AGENT=" + HTTP_USER_AGENT);
+                config.getStreamingMetadata()
+                        .getAuthorization()
+                        .ifPresent(s -> extraProperties.add("AUTHORIZATION=" + s));
+                updateEngineApplyPayload(payloadSpec, extraProperties);
+            } else {
+                Log.e(TAG, "PrepareStreamingService failed, result code is " + code);
+                setUpdaterState(UpdaterStates.ERROR);
+            }
+        });
+    }
+
+    private List<String> prepareExtraProperties(UpdateConfig config) {
+        List<String> extraProperties = new ArrayList<>();
+
+        if (!config.getAbConfig().getForceSwitchSlot()) {
+            // Disable switch slot on reboot, which is enabled by default.
+            // User will enable it manually by clicking "Switch Slot" button on the screen.
+            extraProperties.add(UpdateEngineProperties.PROPERTY_DISABLE_SWITCH_SLOT_ON_REBOOT);
+        }
+        return extraProperties;
+    }
+
+    /**
+     * Applies given payload.
+     *
+     * <p>UpdateEngine works asynchronously. This method doesn't wait until
+     * end of the update.</p>
+     *
+     * <p>It's possible that the update engine throws a generic error, such as upon seeing invalid
+     * payload properties (which come from OTA packages), or failing to set up the network
+     * with the given id.</p>
+     *
+     * @param payloadSpec contains url, offset and size to {@code PAYLOAD_BINARY_FILE_NAME}
+     * @param extraProperties additional properties to pass to {@link UpdateEngine#applyPayload}
+     */
+    private void updateEngineApplyPayload(PayloadSpec payloadSpec, List<String> extraProperties) {
+        mLastPayloadSpec = payloadSpec;
+
+        ArrayList<String> properties = new ArrayList<>(payloadSpec.getProperties());
+        if (extraProperties != null) {
+            properties.addAll(extraProperties);
+        }
+        try {
+            mUpdateEngine.applyPayload(
+                    payloadSpec.getUrl(),
+                    payloadSpec.getOffset(),
+                    payloadSpec.getSize(),
+                    properties.toArray(new String[0]));
+        } catch (Exception e) {
+            Log.e(TAG, "UpdateEngine failed to apply the update", e);
+            setUpdaterState(UpdaterStates.ERROR);
+        }
+    }
+
+    /**
+     * Sets the new slot that has the updated partitions as the active slot,
+     * which device will boot into next time.
+     * This method is only supposed to be called after the payload is applied.
+     *
+     * Invoking {@link UpdateEngine#applyPayload} with the same payload url, offset, size
+     * and payload metadata headers doesn't trigger new update. It can be used to just switch
+     * active A/B slot.
+     *
+     * {@link UpdateEngine#applyPayload} might take several seconds to finish, and it will
+     * invoke callbacks {@link this#onStatusUpdate} and {@link this#onPayloadApplicationComplete)}.
+     */
+    public void setSwitchSlotOnReboot() {
+        Log.d(TAG, "setSwitchSlotOnReboot invoked");
+        List<String> extraProperties = new ArrayList<>();
+        // PROPERTY_SKIP_POST_INSTALL should be passed on to skip post-installation hooks.
+        extraProperties.add(UpdateEngineProperties.PROPERTY_SKIP_POST_INSTALL);
+        // It sets property SWITCH_SLOT_ON_REBOOT=1 by default.
+        // HTTP headers are not required, UpdateEngine is not expected to stream payload.
+        updateEngineApplyPayload(mLastPayloadSpec, extraProperties);
+    }
+
+    private void onStatusUpdate(int status, float progress) {
+        int previousStatus = mUpdateEngineStatus.get();
+        mUpdateEngineStatus.set(status);
+        mProgress.set(progress);
+
+        getOnProgressUpdateCallback().ifPresent(callback -> callback.accept(progress));
+
+        if (previousStatus != status) {
+            getOnEngineStatusUpdateCallback().ifPresent(callback -> callback.accept(status));
+        }
+    }
+
+    private void onPayloadApplicationComplete(int errorCode) {
+        Log.d(TAG, "onPayloadApplicationComplete invoked, errorCode=" + errorCode);
+        mEngineErrorCode.set(errorCode);
+        if (errorCode == UpdateEngine.ErrorCodeConstants.SUCCESS
+                || errorCode == UpdateEngineErrorCodes.UPDATED_BUT_NOT_ACTIVE) {
+            setUpdaterState(UpdaterStates.FINISHED);
+        } else if (errorCode != UpdateEngineErrorCodes.USER_CANCELLED) {
+            setUpdaterState(UpdaterStates.ERROR);
+        }
+
+        getOnEngineCompleteCallback()
+                .ifPresent(callback -> callback.accept(errorCode));
+    }
+
+    /**
+     * Helper class to delegate {@code update_engine} callbacks to UpdateManager
+     */
+    class UpdateEngineCallbackImpl extends UpdateEngineCallback {
+        @Override
+        public void onStatusUpdate(int status, float percent) {
+            UpdateManager.this.onStatusUpdate(status, percent);
+        }
+
+        @Override
+        public void onPayloadApplicationComplete(int errorCode) {
+            UpdateManager.this.onPayloadApplicationComplete(errorCode);
+        }
+    }
+
+}
diff --git a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
index 9bab131..9983fe3 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
@@ -22,7 +22,6 @@
 import android.os.Build;
 import android.os.Bundle;
 import android.os.UpdateEngine;
-import android.os.UpdateEngineCallback;
 import android.util.Log;
 import android.view.View;
 import android.widget.ArrayAdapter;
@@ -30,23 +29,17 @@
 import android.widget.ProgressBar;
 import android.widget.Spinner;
 import android.widget.TextView;
-import android.widget.Toast;
 
-import com.example.android.systemupdatersample.PayloadSpec;
 import com.example.android.systemupdatersample.R;
 import com.example.android.systemupdatersample.UpdateConfig;
-import com.example.android.systemupdatersample.services.PrepareStreamingService;
+import com.example.android.systemupdatersample.UpdateManager;
 import com.example.android.systemupdatersample.util.PayloadSpecs;
 import com.example.android.systemupdatersample.util.UpdateConfigs;
 import com.example.android.systemupdatersample.util.UpdateEngineErrorCodes;
-import com.example.android.systemupdatersample.util.UpdateEngineProperties;
 import com.example.android.systemupdatersample.util.UpdateEngineStatuses;
+import com.example.android.systemupdatersample.util.UpdaterStates;
 
-import java.io.IOException;
-import java.util.ArrayList;
 import java.util.List;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * UI for SystemUpdaterSample app.
@@ -55,10 +48,6 @@
 
     private static final String TAG = "MainActivity";
 
-    /** HTTP Header: User-Agent; it will be sent to the server when streaming the payload. */
-    private static final String HTTP_USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
-            + "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36";
-
     private TextView mTextViewBuild;
     private Spinner mSpinnerConfigs;
     private TextView mTextViewConfigsDirHint;
@@ -67,24 +56,16 @@
     private Button mButtonStop;
     private Button mButtonReset;
     private ProgressBar mProgressBar;
-    private TextView mTextViewStatus;
-    private TextView mTextViewCompletion;
+    private TextView mTextViewUpdaterState;
+    private TextView mTextViewEngineStatus;
+    private TextView mTextViewEngineErrorCode;
     private TextView mTextViewUpdateInfo;
     private Button mButtonSwitchSlot;
 
     private List<UpdateConfig> mConfigs;
-    private AtomicInteger mUpdateEngineStatus =
-            new AtomicInteger(UpdateEngine.UpdateStatusConstants.IDLE);
-    private PayloadSpec mLastPayloadSpec;
-    private AtomicBoolean mManualSwitchSlotRequired = new AtomicBoolean(true);
-    private final PayloadSpecs mPayloadSpecs = new PayloadSpecs();
 
-    /**
-     * Listen to {@code update_engine} events.
-     */
-    private UpdateEngineCallbackImpl mUpdateEngineCallback = new UpdateEngineCallbackImpl();
-
-    private final UpdateEngine mUpdateEngine = new UpdateEngine();
+    private final UpdateManager mUpdateManager =
+            new UpdateManager(new UpdateEngine(), new PayloadSpecs());
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -99,8 +80,9 @@
         this.mButtonStop = findViewById(R.id.buttonStop);
         this.mButtonReset = findViewById(R.id.buttonReset);
         this.mProgressBar = findViewById(R.id.progressBar);
-        this.mTextViewStatus = findViewById(R.id.textViewStatus);
-        this.mTextViewCompletion = findViewById(R.id.textViewCompletion);
+        this.mTextViewUpdaterState = findViewById(R.id.textViewUpdaterState);
+        this.mTextViewEngineStatus = findViewById(R.id.textViewEngineStatus);
+        this.mTextViewEngineErrorCode = findViewById(R.id.textViewEngineErrorCode);
         this.mTextViewUpdateInfo = findViewById(R.id.textViewUpdateInfo);
         this.mButtonSwitchSlot = findViewById(R.id.buttonSwitchSlot);
 
@@ -109,15 +91,32 @@
         uiReset();
         loadUpdateConfigs();
 
-        this.mUpdateEngine.bind(mUpdateEngineCallback);
+        this.mUpdateManager.setOnStateChangeCallback(this::onUpdaterStateChange);
+        this.mUpdateManager.setOnEngineStatusUpdateCallback(this::onEngineStatusUpdate);
+        this.mUpdateManager.setOnEngineCompleteCallback(this::onEnginePayloadApplicationComplete);
+        this.mUpdateManager.setOnProgressUpdateCallback(this::onProgressUpdate);
     }
 
     @Override
     protected void onDestroy() {
-        this.mUpdateEngine.unbind();
+        this.mUpdateManager.setOnEngineStatusUpdateCallback(null);
+        this.mUpdateManager.setOnProgressUpdateCallback(null);
+        this.mUpdateManager.setOnEngineCompleteCallback(null);
         super.onDestroy();
     }
 
+    @Override
+    protected void onResume() {
+        super.onResume();
+        this.mUpdateManager.bind();
+    }
+
+    @Override
+    protected void onPause() {
+        this.mUpdateManager.unbind();
+        super.onPause();
+    }
+
     /**
      * reload button is clicked
      */
@@ -147,7 +146,8 @@
                 .setIcon(android.R.drawable.ic_dialog_alert)
                 .setPositiveButton(android.R.string.ok, (dialog, whichButton) -> {
                     uiSetUpdating();
-                    applyUpdate(getSelectedConfig());
+                    uiResetEngineText();
+                    mUpdateManager.applyUpdate(this, getSelectedConfig());
                 })
                 .setNegativeButton(android.R.string.cancel, null)
                 .show();
@@ -162,7 +162,7 @@
                 .setMessage("Do you really want to cancel running update?")
                 .setIcon(android.R.drawable.ic_dialog_alert)
                 .setPositiveButton(android.R.string.ok, (dialog, whichButton) -> {
-                    stopRunningUpdate();
+                    mUpdateManager.cancelRunningUpdate();
                 })
                 .setNegativeButton(android.R.string.cancel, null).show();
     }
@@ -177,7 +177,7 @@
                         + " and restore old version?")
                 .setIcon(android.R.drawable.ic_dialog_alert)
                 .setPositiveButton(android.R.string.ok, (dialog, whichButton) -> {
-                    resetUpdate();
+                    mUpdateManager.resetUpdate();
                 })
                 .setNegativeButton(android.R.string.cancel, null).show();
     }
@@ -186,34 +186,39 @@
      * switch slot button clicked
      */
     public void onSwitchSlotClick(View view) {
-        setSwitchSlotOnReboot();
+        mUpdateManager.setSwitchSlotOnReboot();
     }
 
     /**
-     * Invoked when anything changes. The value of {@code status} will
-     * be one of the values from {@link UpdateEngine.UpdateStatusConstants},
-     * and {@code percent} will be from {@code 0.0} to {@code 1.0}.
+     * Invoked when SystemUpdaterSample app state changes.
+     * Value of {@code state} will be one of the
+     * values from {@link UpdaterStates}.
      */
-    private void onStatusUpdate(int status, float percent) {
-        mProgressBar.setProgress((int) (100 * percent));
-        if (mUpdateEngineStatus.get() != status) {
-            mUpdateEngineStatus.set(status);
-            runOnUiThread(() -> {
-                Log.e("UpdateEngine", "StatusUpdate - status="
-                        + UpdateEngineStatuses.getStatusText(status)
-                        + "/" + status);
-                Toast.makeText(this, "Update Status changed", Toast.LENGTH_LONG)
-                        .show();
-                if (status == UpdateEngine.UpdateStatusConstants.IDLE) {
-                    Log.d(TAG, "status changed, resetting ui");
-                    uiReset();
-                } else {
-                    Log.d(TAG, "status changed, setting ui to updating mode");
-                    uiSetUpdating();
-                }
-                setUiStatus(status);
-            });
-        }
+    private void onUpdaterStateChange(int state) {
+        Log.i(TAG, "onUpdaterStateChange invoked state=" + state);
+        runOnUiThread(() -> {
+            setUiUpdaterState(state);
+        });
+    }
+
+    /**
+     * Invoked when {@link UpdateEngine} status changes. Value of {@code status} will
+     * be one of the values from {@link UpdateEngine.UpdateStatusConstants}.
+     */
+    private void onEngineStatusUpdate(int status) {
+        runOnUiThread(() -> {
+            Log.e(TAG, "StatusUpdate - status="
+                    + UpdateEngineStatuses.getStatusText(status)
+                    + "/" + status);
+            if (status == UpdateEngine.UpdateStatusConstants.IDLE) {
+                Log.d(TAG, "status changed, resetting ui");
+                uiReset();
+            } else {
+                Log.d(TAG, "status changed, setting ui to updating mode");
+                uiSetUpdating();
+            }
+            setUiEngineStatus(status);
+        });
     }
 
     /**
@@ -221,20 +226,19 @@
      * unsuccessfully. The value of {@code errorCode} will be one of the
      * values from {@link UpdateEngine.ErrorCodeConstants}.
      */
-    private void onPayloadApplicationComplete(int errorCode) {
-        final String state = UpdateEngineErrorCodes.isUpdateSucceeded(errorCode)
+    private void onEnginePayloadApplicationComplete(int errorCode) {
+        final String completionState = UpdateEngineErrorCodes.isUpdateSucceeded(errorCode)
                 ? "SUCCESS"
                 : "FAILURE";
         runOnUiThread(() -> {
-            Log.i("UpdateEngine",
+            Log.i(TAG,
                     "Completed - errorCode="
                     + UpdateEngineErrorCodes.getCodeName(errorCode) + "/" + errorCode
-                    + " " + state);
-            Toast.makeText(this, "Update completed", Toast.LENGTH_LONG).show();
-            setUiCompletion(errorCode);
+                    + " " + completionState);
+            setUiEngineErrorCode(errorCode);
             if (errorCode == UpdateEngineErrorCodes.UPDATED_BUT_NOT_ACTIVE) {
                 // if update was successfully applied.
-                if (mManualSwitchSlotRequired.get()) {
+                if (mUpdateManager.isManualSwitchSlotRequired()) {
                     // Show "Switch Slot" button.
                     uiShowSwitchSlotInfo();
                 }
@@ -242,6 +246,13 @@
         });
     }
 
+    /**
+     * Invoked when update progress changes.
+     */
+    private void onProgressUpdate(double progress) {
+        mProgressBar.setProgress((int) (100 * progress));
+    }
+
     /** resets ui */
     private void uiReset() {
         mTextViewBuild.setText(Build.DISPLAY);
@@ -253,11 +264,15 @@
         mProgressBar.setProgress(0);
         mProgressBar.setEnabled(false);
         mProgressBar.setVisibility(ProgressBar.INVISIBLE);
-        mTextViewStatus.setText(R.string.unknown);
-        mTextViewCompletion.setText(R.string.unknown);
         uiHideSwitchSlotInfo();
     }
 
+    private void uiResetEngineText() {
+        mTextViewEngineStatus.setText(R.string.unknown);
+        mTextViewEngineErrorCode.setText(R.string.unknown);
+        // Note: Do not reset mTextViewUpdaterState; UpdateManager notifies properly.
+    }
+
     /** sets ui updating mode */
     private void uiSetUpdating() {
         mTextViewBuild.setText(Build.DISPLAY);
@@ -291,20 +306,25 @@
     /**
      * @param status update engine status code
      */
-    private void setUiStatus(int status) {
+    private void setUiEngineStatus(int status) {
         String statusText = UpdateEngineStatuses.getStatusText(status);
-        mTextViewStatus.setText(statusText + "/" + status);
+        mTextViewEngineStatus.setText(statusText + "/" + status);
     }
 
     /**
      * @param errorCode update engine error code
      */
-    private void setUiCompletion(int errorCode) {
-        final String state = UpdateEngineErrorCodes.isUpdateSucceeded(errorCode)
-                ? "SUCCESS"
-                : "FAILURE";
+    private void setUiEngineErrorCode(int errorCode) {
         String errorText = UpdateEngineErrorCodes.getCodeName(errorCode);
-        mTextViewCompletion.setText(state + " " + errorText + "/" + errorCode);
+        mTextViewEngineErrorCode.setText(errorText + "/" + errorCode);
+    }
+
+    /**
+     * @param state updater sample state
+     */
+    private void setUiUpdaterState(int state) {
+        String stateText = UpdaterStates.getStateText(state);
+        mTextViewUpdaterState.setText(stateText + "/" + state);
     }
 
     private void loadConfigsToSpinner(List<UpdateConfig> configs) {
@@ -321,143 +341,4 @@
         return mConfigs.get(mSpinnerConfigs.getSelectedItemPosition());
     }
 
-    /**
-     * Applies the given update
-     */
-    private void applyUpdate(final UpdateConfig config) {
-        List<String> extraProperties = new ArrayList<>();
-
-        if (!config.getAbConfig().getForceSwitchSlot()) {
-            // Disable switch slot on reboot, which is enabled by default.
-            // User will enable it manually by clicking "Switch Slot" button on the screen.
-            extraProperties.add(UpdateEngineProperties.PROPERTY_DISABLE_SWITCH_SLOT_ON_REBOOT);
-            mManualSwitchSlotRequired.set(true);
-        } else {
-            mManualSwitchSlotRequired.set(false);
-        }
-
-        if (config.getInstallType() == UpdateConfig.AB_INSTALL_TYPE_NON_STREAMING) {
-            PayloadSpec payload;
-            try {
-                payload = mPayloadSpecs.forNonStreaming(config.getUpdatePackageFile());
-            } catch (IOException e) {
-                Log.e(TAG, "Error creating payload spec", e);
-                Toast.makeText(this, "Error creating payload spec", Toast.LENGTH_LONG)
-                        .show();
-                return;
-            }
-            updateEngineApplyPayload(payload, extraProperties);
-        } else {
-            Log.d(TAG, "Starting PrepareStreamingService");
-            PrepareStreamingService.startService(this, config, (code, payloadSpec) -> {
-                if (code == PrepareStreamingService.RESULT_CODE_SUCCESS) {
-                    extraProperties.add("USER_AGENT=" + HTTP_USER_AGENT);
-                    config.getStreamingMetadata()
-                            .getAuthorization()
-                            .ifPresent(s -> extraProperties.add("AUTHORIZATION=" + s));
-                    updateEngineApplyPayload(payloadSpec, extraProperties);
-                } else {
-                    Log.e(TAG, "PrepareStreamingService failed, result code is " + code);
-                    Toast.makeText(
-                            MainActivity.this,
-                            "PrepareStreamingService failed, result code is " + code,
-                            Toast.LENGTH_LONG).show();
-                }
-            });
-        }
-    }
-
-    /**
-     * Applies given payload.
-     *
-     * UpdateEngine works asynchronously. This method doesn't wait until
-     * end of the update.
-     *
-     * @param payloadSpec contains url, offset and size to {@code PAYLOAD_BINARY_FILE_NAME}
-     * @param extraProperties additional properties to pass to {@link UpdateEngine#applyPayload}
-     */
-    private void updateEngineApplyPayload(PayloadSpec payloadSpec, List<String> extraProperties) {
-        mLastPayloadSpec = payloadSpec;
-
-        ArrayList<String> properties = new ArrayList<>(payloadSpec.getProperties());
-        if (extraProperties != null) {
-            properties.addAll(extraProperties);
-        }
-        try {
-            mUpdateEngine.applyPayload(
-                    payloadSpec.getUrl(),
-                    payloadSpec.getOffset(),
-                    payloadSpec.getSize(),
-                    properties.toArray(new String[0]));
-        } catch (Exception e) {
-            Log.e(TAG, "UpdateEngine failed to apply the update", e);
-            Toast.makeText(
-                    this,
-                    "UpdateEngine failed to apply the update",
-                    Toast.LENGTH_LONG).show();
-        }
-    }
-
-    /**
-     * Sets the new slot that has the updated partitions as the active slot,
-     * which device will boot into next time.
-     * This method is only supposed to be called after the payload is applied.
-     *
-     * Invoking {@link UpdateEngine#applyPayload} with the same payload url, offset, size
-     * and payload metadata headers doesn't trigger new update. It can be used to just switch
-     * active A/B slot.
-     *
-     * {@link UpdateEngine#applyPayload} might take several seconds to finish, and it will
-     * invoke callbacks {@link this#onStatusUpdate} and {@link this#onPayloadApplicationComplete)}.
-     */
-    private void setSwitchSlotOnReboot() {
-        Log.d(TAG, "setSwitchSlotOnReboot invoked");
-        List<String> extraProperties = new ArrayList<>();
-        // PROPERTY_SKIP_POST_INSTALL should be passed on to skip post-installation hooks.
-        extraProperties.add(UpdateEngineProperties.PROPERTY_SKIP_POST_INSTALL);
-        // It sets property SWITCH_SLOT_ON_REBOOT=1 by default.
-        // HTTP headers are not required, UpdateEngine is not expected to stream payload.
-        updateEngineApplyPayload(mLastPayloadSpec, extraProperties);
-        uiHideSwitchSlotInfo();
-    }
-
-    /**
-     * Requests update engine to stop any ongoing update. If an update has been applied,
-     * leave it as is.
-     */
-    private void stopRunningUpdate() {
-        try {
-            mUpdateEngine.cancel();
-        } catch (Exception e) {
-            Log.w(TAG, "UpdateEngine failed to stop the ongoing update", e);
-        }
-    }
-
-    /**
-     * Resets update engine to IDLE state. Requests to cancel any onging update, or to revert if an
-     * update has been applied.
-     */
-    private void resetUpdate() {
-        try {
-            mUpdateEngine.resetStatus();
-        } catch (Exception e) {
-            Log.w(TAG, "UpdateEngine failed to reset the update", e);
-        }
-    }
-
-    /**
-     * Helper class to delegate {@code update_engine} callbacks to MainActivity
-     */
-    class UpdateEngineCallbackImpl extends UpdateEngineCallback {
-        @Override
-        public void onStatusUpdate(int status, float percent) {
-            MainActivity.this.onStatusUpdate(status, percent);
-        }
-
-        @Override
-        public void onPayloadApplicationComplete(int errorCode) {
-            MainActivity.this.onPayloadApplicationComplete(errorCode);
-        }
-    }
-
 }
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java b/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java
index b98b97c..f062317 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/util/PayloadSpecs.java
@@ -32,7 +32,9 @@
 import java.util.zip.ZipFile;
 
 /** The helper class that creates {@link PayloadSpec}. */
-public final class PayloadSpecs {
+public class PayloadSpecs {
+
+    public PayloadSpecs() {}
 
     /**
      * The payload PAYLOAD_ENTRY is stored in the zip package to comply with the Android OTA package
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java b/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java
index 6d319c5..7d55ff8 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/util/UpdateEngineErrorCodes.java
@@ -34,7 +34,9 @@
     * Error code from the update engine. Values must agree with the ones in
     * system/update_engine/common/error_code.h.
     */
+    public static final int UNKNOWN = -1;
     public static final int UPDATED_BUT_NOT_ACTIVE = 52;
+    public static final int USER_CANCELLED = 48;
 
     private static final SparseArray<String> CODE_TO_NAME_MAP = new SparseArray<>();
 
@@ -60,7 +62,7 @@
      * Completion codes returned by update engine indicating that the update
      * was successfully applied.
      */
-    private static final Set<Integer> SUCCEEDED_COMPLETION_CODES = new HashSet<Integer>(
+    private static final Set<Integer> SUCCEEDED_COMPLETION_CODES = new HashSet<>(
             Arrays.asList(UpdateEngine.ErrorCodeConstants.SUCCESS,
                     // UPDATED_BUT_NOT_ACTIVE is returned when the payload is
                     // successfully applied but the
diff --git a/updater_sample/src/com/example/android/systemupdatersample/util/UpdaterStates.java b/updater_sample/src/com/example/android/systemupdatersample/util/UpdaterStates.java
new file mode 100644
index 0000000..fc20a79
--- /dev/null
+++ b/updater_sample/src/com/example/android/systemupdatersample/util/UpdaterStates.java
@@ -0,0 +1,50 @@
+/*
+ * 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.
+ */
+
+package com.example.android.systemupdatersample.util;
+
+import android.util.SparseArray;
+
+/**
+ * SystemUpdaterSample app state.
+ */
+public class UpdaterStates {
+
+    public static final int IDLE = 0;
+    public static final int ERROR = 1;
+    public static final int RUNNING = 2;
+    public static final int PAUSED = 3;
+    public static final int FINISHED = 4;
+
+    private static final SparseArray<String> STATE_MAP = new SparseArray<>();
+
+    static {
+        STATE_MAP.put(0, "IDLE");
+        STATE_MAP.put(1, "ERROR");
+        STATE_MAP.put(2, "RUNNING");
+        STATE_MAP.put(3, "PAUSED");
+        STATE_MAP.put(4, "FINISHED");
+    }
+
+    /**
+     * converts status code to status name
+     */
+    public static String getStateText(int state) {
+        return STATE_MAP.get(state);
+    }
+
+    private UpdaterStates() {}
+}
diff --git a/updater_sample/tests/Android.mk b/updater_sample/tests/Android.mk
index a1a4664..9aec372 100644
--- a/updater_sample/tests/Android.mk
+++ b/updater_sample/tests/Android.mk
@@ -23,9 +23,9 @@
 LOCAL_JAVA_LIBRARIES := \
     android.test.base.stubs \
     android.test.runner.stubs \
-    guava \
+    guava
+LOCAL_STATIC_JAVA_LIBRARIES := android-support-test \
     mockito-target-minus-junit4
-LOCAL_STATIC_JAVA_LIBRARIES := android-support-test
 LOCAL_INSTRUMENTATION_FOR := SystemUpdaterSample
 LOCAL_PROGUARD_ENABLED := disabled
 
diff --git a/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateManagerTest.java b/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateManagerTest.java
new file mode 100644
index 0000000..0657a5e
--- /dev/null
+++ b/updater_sample/tests/src/com/example/android/systemupdatersample/UpdateManagerTest.java
@@ -0,0 +1,92 @@
+/*
+ * 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.
+ */
+
+package com.example.android.systemupdatersample;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.doAnswer;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.os.UpdateEngine;
+import android.os.UpdateEngineCallback;
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+
+import com.example.android.systemupdatersample.util.PayloadSpecs;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.mockito.junit.MockitoRule;
+
+import java.util.function.IntConsumer;
+
+/**
+ * Tests for {@link UpdateManager}
+ */
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class UpdateManagerTest {
+
+    @Rule
+    public MockitoRule mockito = MockitoJUnit.rule();
+
+    @Mock
+    private UpdateEngine mUpdateEngine;
+    @Mock
+    private PayloadSpecs mPayloadSpecs;
+    private UpdateManager mUpdateManager;
+
+    @Before
+    public void setUp() {
+        mUpdateManager = new UpdateManager(mUpdateEngine, mPayloadSpecs);
+    }
+
+    @Test
+    public void storesProgressThenInvokesCallbacks() {
+        IntConsumer statusUpdateCallback = mock(IntConsumer.class);
+
+        // When UpdateManager is bound to update_engine, it passes
+        // UpdateManager.UpdateEngineCallbackImpl as a callback to update_engine.
+        when(mUpdateEngine.bind(any(UpdateEngineCallback.class))).thenAnswer(answer -> {
+            UpdateEngineCallback callback = answer.getArgument(0);
+            callback.onStatusUpdate(/*engineStatus*/ 4, /*engineProgress*/ 0.2f);
+            return null;
+        });
+
+        mUpdateManager.setOnEngineStatusUpdateCallback(statusUpdateCallback);
+
+        // Making sure that manager.getProgress() returns correct progress
+        // in "onEngineStatusUpdate" callback.
+        doAnswer(answer -> {
+            assertEquals(0.2f, mUpdateManager.getProgress(), 1E-5);
+            return null;
+        }).when(statusUpdateCallback).accept(anyInt());
+
+        mUpdateManager.bind();
+
+        verify(statusUpdateCallback, times(1)).accept(4);
+    }
+
+}
diff --git a/updater_sample/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java b/updater_sample/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java
deleted file mode 100644
index 0101416..0000000
--- a/updater_sample/tests/src/com/example/android/systemupdatersample/ui/MainActivityTest.java
+++ /dev/null
@@ -1,48 +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.
- */
-
-package com.example.android.systemupdatersample.ui;
-
-import static org.junit.Assert.assertNotNull;
-
-import android.support.test.filters.MediumTest;
-import android.support.test.rule.ActivityTestRule;
-import android.support.test.runner.AndroidJUnit4;
-
-import org.junit.Rule;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-/**
- * Make sure that the main launcher activity opens up properly, which will be
- * verified by {@link #activityLaunches}.
- */
-@RunWith(AndroidJUnit4.class)
-@MediumTest
-public class MainActivityTest {
-
-    @Rule
-    public final ActivityTestRule<MainActivity> mActivityRule =
-            new ActivityTestRule<>(MainActivity.class);
-
-    /**
-     * Verifies that the activity under test can be launched.
-     */
-    @Test
-    public void activityLaunches() {
-        assertNotNull(mActivityRule.getActivity());
-    }
-}