diff --git a/Android.bp b/Android.bp
index 22407e0..f8c6a4b 100644
--- a/Android.bp
+++ b/Android.bp
@@ -4,4 +4,5 @@
     "edify",
     "otafault",
     "otautil",
+    "uncrypt",
 ]
diff --git a/Android.mk b/Android.mk
index 985131b..d9966b7 100644
--- a/Android.mk
+++ b/Android.mk
@@ -263,6 +263,5 @@
     $(LOCAL_PATH)/minui/Android.mk \
     $(LOCAL_PATH)/tests/Android.mk \
     $(LOCAL_PATH)/tools/Android.mk \
-    $(LOCAL_PATH)/uncrypt/Android.mk \
     $(LOCAL_PATH)/updater/Android.mk \
     $(LOCAL_PATH)/update_verifier/Android.mk \
diff --git a/applypatch/applypatch.cpp b/applypatch/applypatch.cpp
index 2153b5f..41a72eb 100644
--- a/applypatch/applypatch.cpp
+++ b/applypatch/applypatch.cpp
@@ -651,11 +651,11 @@
 
   int result;
   if (use_bsdiff) {
-    result = ApplyBSDiffPatch(source_file.data.data(), source_file.data.size(), patch.get(), 0,
-                              sink, &ctx);
+    result =
+        ApplyBSDiffPatch(source_file.data.data(), source_file.data.size(), *patch, 0, sink, &ctx);
   } else {
-    result = ApplyImagePatch(source_file.data.data(), source_file.data.size(), patch.get(), sink,
-                             &ctx, bonus_data);
+    result = ApplyImagePatch(source_file.data.data(), source_file.data.size(), *patch, sink, &ctx,
+                             bonus_data);
   }
 
   if (result != 0) {
diff --git a/applypatch/bspatch.cpp b/applypatch/bspatch.cpp
index c291464..912dbbd 100644
--- a/applypatch/bspatch.cpp
+++ b/applypatch/bspatch.cpp
@@ -26,7 +26,7 @@
 #include <string>
 
 #include <android-base/logging.h>
-#include <bspatch.h>
+#include <bsdiff/bspatch.h>
 #include <openssl/sha.h>
 
 #include "applypatch/applypatch.h"
@@ -65,7 +65,7 @@
         );
 }
 
-int ApplyBSDiffPatch(const unsigned char* old_data, size_t old_size, const Value* patch,
+int ApplyBSDiffPatch(const unsigned char* old_data, size_t old_size, const Value& patch,
                      size_t patch_offset, SinkFn sink, SHA_CTX* ctx) {
   auto sha_sink = [&sink, &ctx](const uint8_t* data, size_t len) {
     len = sink(data, len);
@@ -73,22 +73,20 @@
     return len;
   };
 
-  CHECK(patch != nullptr);
-  CHECK_LE(patch_offset, patch->data.size());
+  CHECK_LE(patch_offset, patch.data.size());
 
   int result = bsdiff::bspatch(old_data, old_size,
-                               reinterpret_cast<const uint8_t*>(&patch->data[patch_offset]),
-                               patch->data.size() - patch_offset, sha_sink);
+                               reinterpret_cast<const uint8_t*>(&patch.data[patch_offset]),
+                               patch.data.size() - patch_offset, sha_sink);
   if (result != 0) {
     LOG(ERROR) << "bspatch failed, result: " << result;
     // print SHA1 of the patch in the case of a data error.
     if (result == 2) {
       uint8_t digest[SHA_DIGEST_LENGTH];
-      SHA1(reinterpret_cast<const uint8_t*>(patch->data.data() + patch_offset),
-           patch->data.size() - patch_offset, digest);
+      SHA1(reinterpret_cast<const uint8_t*>(patch.data.data() + patch_offset),
+           patch.data.size() - patch_offset, digest);
       std::string patch_sha1 = print_sha1(digest);
-      LOG(ERROR) << "Patch may be corrupted, offset: " << patch_offset << ", SHA1: "
-                 << patch_sha1;
+      LOG(ERROR) << "Patch may be corrupted, offset: " << patch_offset << ", SHA1: " << patch_sha1;
     }
   }
   return result;
diff --git a/applypatch/imgpatch.cpp b/applypatch/imgpatch.cpp
index 25ba0a1..3682d61 100644
--- a/applypatch/imgpatch.cpp
+++ b/applypatch/imgpatch.cpp
@@ -50,7 +50,7 @@
 // This function is a wrapper of ApplyBSDiffPatch(). It has a custom sink function to deflate the
 // patched data and stream the deflated data to output.
 static bool ApplyBSDiffPatchAndStreamOutput(const uint8_t* src_data, size_t src_len,
-                                            const Value* patch, size_t patch_offset,
+                                            const Value& patch, size_t patch_offset,
                                             const char* deflate_header, SinkFn sink, SHA_CTX* ctx) {
   size_t expected_target_length = static_cast<size_t>(Read8(deflate_header + 32));
   int level = Read4(deflate_header + 40);
@@ -135,48 +135,39 @@
 int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const unsigned char* patch_data,
                     size_t patch_size, SinkFn sink) {
   Value patch(VAL_BLOB, std::string(reinterpret_cast<const char*>(patch_data), patch_size));
-
-  return ApplyImagePatch(old_data, old_size, &patch, sink, nullptr, nullptr);
+  return ApplyImagePatch(old_data, old_size, patch, sink, nullptr, nullptr);
 }
 
-/*
- * Apply the patch given in 'patch_filename' to the source data given
- * by (old_data, old_size).  Write the patched output to the 'output'
- * file, and update the SHA context with the output data as well.
- * Return 0 on success.
- */
-int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const Value* patch, SinkFn sink,
+int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const Value& patch, SinkFn sink,
                     SHA_CTX* ctx, const Value* bonus_data) {
-  if (patch->data.size() < 12) {
+  if (patch.data.size() < 12) {
     printf("patch too short to contain header\n");
     return -1;
   }
 
-  // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW.
-  // (IMGDIFF1, which is no longer supported, used CHUNK_NORMAL and
-  // CHUNK_GZIP.)
-  size_t pos = 12;
-  const char* header = &patch->data[0];
-  if (memcmp(header, "IMGDIFF2", 8) != 0) {
+  // IMGDIFF2 uses CHUNK_NORMAL, CHUNK_DEFLATE, and CHUNK_RAW. (IMGDIFF1, which is no longer
+  // supported, used CHUNK_NORMAL and CHUNK_GZIP.)
+  const char* const patch_header = patch.data.data();
+  if (memcmp(patch_header, "IMGDIFF2", 8) != 0) {
     printf("corrupt patch file header (magic number)\n");
     return -1;
   }
 
-  int num_chunks = Read4(header + 8);
-
+  int num_chunks = Read4(patch_header + 8);
+  size_t pos = 12;
   for (int i = 0; i < num_chunks; ++i) {
     // each chunk's header record starts with 4 bytes.
-    if (pos + 4 > patch->data.size()) {
+    if (pos + 4 > patch.data.size()) {
       printf("failed to read chunk %d record\n", i);
       return -1;
     }
-    int type = Read4(&patch->data[pos]);
+    int type = Read4(patch_header + pos);
     pos += 4;
 
     if (type == CHUNK_NORMAL) {
-      const char* normal_header = &patch->data[pos];
+      const char* normal_header = patch_header + pos;
       pos += 24;
-      if (pos > patch->data.size()) {
+      if (pos > patch.data.size()) {
         printf("failed to read chunk %d normal header data\n", i);
         return -1;
       }
@@ -194,30 +185,32 @@
         return -1;
       }
     } else if (type == CHUNK_RAW) {
-      const char* raw_header = &patch->data[pos];
+      const char* raw_header = patch_header + pos;
       pos += 4;
-      if (pos > patch->data.size()) {
+      if (pos > patch.data.size()) {
         printf("failed to read chunk %d raw header data\n", i);
         return -1;
       }
 
       size_t data_len = static_cast<size_t>(Read4(raw_header));
 
-      if (pos + data_len > patch->data.size()) {
+      if (pos + data_len > patch.data.size()) {
         printf("failed to read chunk %d raw data\n", i);
         return -1;
       }
-      if (ctx) SHA1_Update(ctx, &patch->data[pos], data_len);
-      if (sink(reinterpret_cast<const unsigned char*>(&patch->data[pos]), data_len) != data_len) {
+      if (ctx) {
+        SHA1_Update(ctx, patch_header + pos, data_len);
+      }
+      if (sink(reinterpret_cast<const unsigned char*>(patch_header + pos), data_len) != data_len) {
         printf("failed to write chunk %d raw data\n", i);
         return -1;
       }
       pos += data_len;
     } else if (type == CHUNK_DEFLATE) {
       // deflate chunks have an additional 60 bytes in their chunk header.
-      const char* deflate_header = &patch->data[pos];
+      const char* deflate_header = patch_header + pos;
       pos += 60;
-      if (pos > patch->data.size()) {
+      if (pos > patch.data.size()) {
         printf("failed to read chunk %d deflate header data\n", i);
         return -1;
       }
diff --git a/applypatch/include/applypatch/applypatch.h b/applypatch/include/applypatch/applypatch.h
index bcb8a41..6d7ffd7 100644
--- a/applypatch/include/applypatch/applypatch.h
+++ b/applypatch/include/applypatch/applypatch.h
@@ -45,6 +45,7 @@
 using SinkFn = std::function<size_t(const unsigned char*, size_t)>;
 
 // applypatch.cpp
+
 int ShowLicenses();
 size_t FreeSpaceForFile(const char* filename);
 int CacheSizeCheck(size_t bytes);
@@ -66,15 +67,25 @@
 int SaveFileContents(const char* filename, const FileContents* file);
 
 // bspatch.cpp
+
 void ShowBSDiffLicense();
-int ApplyBSDiffPatch(const unsigned char* old_data, size_t old_size, const Value* patch,
+
+// Applies the bsdiff-patch given in 'patch' (from offset 'patch_offset' to the end) to the source
+// data given by (old_data, old_size). Writes the patched output through the given 'sink', and
+// updates the SHA-1 context with the output data. Returns 0 on success.
+int ApplyBSDiffPatch(const unsigned char* old_data, size_t old_size, const Value& patch,
                      size_t patch_offset, SinkFn sink, SHA_CTX* ctx);
 
 // imgpatch.cpp
-int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const Value* patch, SinkFn sink,
+
+// Applies the imgdiff-patch given in 'patch' to the source data given by (old_data, old_size), with
+// the optional bonus data. Writes the patched output through the given 'sink', and updates the
+// SHA-1 context with the output data. Returns 0 on success.
+int ApplyImagePatch(const unsigned char* old_data, size_t old_size, const Value& patch, SinkFn sink,
                     SHA_CTX* ctx, const Value* bonus_data);
 
 // freecache.cpp
+
 int MakeFreeSpaceOnCache(size_t bytes_needed);
 
 #endif
diff --git a/otautil/include/otautil/rangeset.h b/otautil/include/otautil/rangeset.h
index af8ae2d..e91d02c 100644
--- a/otautil/include/otautil/rangeset.h
+++ b/otautil/include/otautil/rangeset.h
@@ -49,6 +49,14 @@
   // bounds. For example, "3,5" contains blocks 3 and 4. So "3,5" and "5,7" are not overlapped.
   bool Overlaps(const RangeSet& other) const;
 
+  // Returns a vector of RangeSets that contain the same set of blocks represented by the current
+  // RangeSet. The RangeSets in the vector contain similar number of blocks, with a maximum delta
+  // of 1-block between any two of them. For example, 14 blocks would be split into 4 + 4 + 3 + 3,
+  // as opposed to 4 + 4 + 4 + 2. If the total number of blocks (T) is less than groups, it
+  // returns a vector of T 1-block RangeSets. Otherwise the number of the returned RangeSets must
+  // equal to groups. The current RangeSet remains intact after the split.
+  std::vector<RangeSet> Split(size_t groups) const;
+
   // Returns the number of Range's in this RangeSet.
   size_t size() const {
     return ranges_.size();
diff --git a/otautil/rangeset.cpp b/otautil/rangeset.cpp
index 532cba4..96955b9 100644
--- a/otautil/rangeset.cpp
+++ b/otautil/rangeset.cpp
@@ -103,6 +103,46 @@
   blocks_ = 0;
 }
 
+std::vector<RangeSet> RangeSet::Split(size_t groups) const {
+  if (ranges_.empty() || groups == 0) return {};
+
+  if (blocks_ < groups) {
+    groups = blocks_;
+  }
+
+  // Evenly distribute blocks, with the first few groups possibly containing one more.
+  size_t mean = blocks_ / groups;
+  std::vector<size_t> blocks_per_group(groups, mean);
+  std::fill_n(blocks_per_group.begin(), blocks_ % groups, mean + 1);
+
+  std::vector<RangeSet> result;
+
+  // Forward iterate Ranges and fill up each group with the desired number of blocks.
+  auto it = ranges_.cbegin();
+  Range range = *it;
+  for (const auto& blocks : blocks_per_group) {
+    RangeSet buffer;
+    size_t needed = blocks;
+    while (needed > 0) {
+      size_t range_blocks = range.second - range.first;
+      if (range_blocks > needed) {
+        // Split the current range and don't advance the iterator.
+        buffer.PushBack({ range.first, range.first + needed });
+        range.first = range.first + needed;
+        break;
+      }
+      buffer.PushBack(range);
+      it++;
+      if (it != ranges_.cend()) {
+        range = *it;
+      }
+      needed -= range_blocks;
+    }
+    result.push_back(std::move(buffer));
+  }
+  return result;
+}
+
 std::string RangeSet::ToString() const {
   if (ranges_.empty()) {
     return "";
diff --git a/tests/unit/rangeset_test.cpp b/tests/unit/rangeset_test.cpp
index 5141bb6..7ae193e 100644
--- a/tests/unit/rangeset_test.cpp
+++ b/tests/unit/rangeset_test.cpp
@@ -123,6 +123,86 @@
   ASSERT_FALSE(RangeSet::Parse("2,5,7").Overlaps(RangeSet::Parse("2,3,5")));
 }
 
+TEST(RangeSetTest, Split) {
+  RangeSet rs1 = RangeSet::Parse("2,1,2");
+  ASSERT_TRUE(rs1);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("2,1,2") }), rs1.Split(1));
+
+  RangeSet rs2 = RangeSet::Parse("2,5,10");
+  ASSERT_TRUE(rs2);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("2,5,8"), RangeSet::Parse("2,8,10") }),
+            rs2.Split(2));
+
+  RangeSet rs3 = RangeSet::Parse("4,0,1,5,10");
+  ASSERT_TRUE(rs3);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("4,0,1,5,7"), RangeSet::Parse("2,7,10") }),
+            rs3.Split(2));
+
+  RangeSet rs4 = RangeSet::Parse("6,1,3,3,4,4,5");
+  ASSERT_TRUE(rs4);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("2,1,3"), RangeSet::Parse("2,3,4"),
+                                    RangeSet::Parse("2,4,5") }),
+            rs4.Split(3));
+
+  RangeSet rs5 = RangeSet::Parse("2,0,10");
+  ASSERT_TRUE(rs5);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("2,0,3"), RangeSet::Parse("2,3,6"),
+                                    RangeSet::Parse("2,6,8"), RangeSet::Parse("2,8,10") }),
+            rs5.Split(4));
+
+  RangeSet rs6 = RangeSet::Parse(
+      "20,0,268,269,271,286,447,8350,32770,33022,98306,98558,163842,164094,196609,204800,229378,"
+      "229630,294914,295166,457564");
+  ASSERT_TRUE(rs6);
+  size_t rs6_blocks = rs6.blocks();
+  auto splits = rs6.Split(4);
+  ASSERT_EQ(
+      (std::vector<RangeSet>{
+          RangeSet::Parse("12,0,268,269,271,286,447,8350,32770,33022,98306,98558,118472"),
+          RangeSet::Parse("8,118472,163842,164094,196609,204800,229378,229630,237216"),
+          RangeSet::Parse("4,237216,294914,295166,347516"), RangeSet::Parse("2,347516,457564") }),
+      splits);
+  size_t sum = 0;
+  for (const auto& element : splits) {
+    sum += element.blocks();
+  }
+  ASSERT_EQ(rs6_blocks, sum);
+}
+
+TEST(RangeSetTest, Split_EdgeCases) {
+  // Empty RangeSet.
+  RangeSet rs1;
+  ASSERT_FALSE(rs1);
+  ASSERT_EQ((std::vector<RangeSet>{}), rs1.Split(2));
+  ASSERT_FALSE(rs1);
+
+  // Zero group.
+  RangeSet rs2 = RangeSet::Parse("2,1,5");
+  ASSERT_TRUE(rs2);
+  ASSERT_EQ((std::vector<RangeSet>{}), rs2.Split(0));
+
+  // The number of blocks equals to the number of groups.
+  RangeSet rs3 = RangeSet::Parse("2,1,5");
+  ASSERT_TRUE(rs3);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("2,1,2"), RangeSet::Parse("2,2,3"),
+                                    RangeSet::Parse("2,3,4"), RangeSet::Parse("2,4,5") }),
+            rs3.Split(4));
+
+  // Less blocks than the number of groups.
+  RangeSet rs4 = RangeSet::Parse("2,1,5");
+  ASSERT_TRUE(rs4);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("2,1,2"), RangeSet::Parse("2,2,3"),
+                                    RangeSet::Parse("2,3,4"), RangeSet::Parse("2,4,5") }),
+            rs4.Split(8));
+
+  // Less blocks than the number of groups.
+  RangeSet rs5 = RangeSet::Parse("2,0,3");
+  ASSERT_TRUE(rs5);
+  ASSERT_EQ((std::vector<RangeSet>{ RangeSet::Parse("2,0,1"), RangeSet::Parse("2,1,2"),
+                                    RangeSet::Parse("2,2,3") }),
+            rs5.Split(4));
+}
+
 TEST(RangeSetTest, GetBlockNumber) {
   RangeSet rs = RangeSet::Parse("2,1,10");
   ASSERT_EQ(static_cast<size_t>(1), rs.GetBlockNumber(0));
diff --git a/uncrypt/Android.bp b/uncrypt/Android.bp
new file mode 100644
index 0000000..aa56d2f
--- /dev/null
+++ b/uncrypt/Android.bp
@@ -0,0 +1,39 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+cc_binary {
+    name: "uncrypt",
+
+    srcs: [
+        "uncrypt.cpp",
+    ],
+
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+
+    static_libs: [
+        "libbootloader_message",
+        "libotautil",
+        "libfs_mgr",
+        "libbase",
+        "libcutils",
+        "liblog",
+    ],
+
+    init_rc: [
+        "uncrypt.rc",
+    ],
+}
diff --git a/uncrypt/Android.mk b/uncrypt/Android.mk
deleted file mode 100644
index 601f927..0000000
--- a/uncrypt/Android.mk
+++ /dev/null
@@ -1,31 +0,0 @@
-# Copyright (C) 2014 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_SRC_FILES := uncrypt.cpp
-LOCAL_MODULE := uncrypt
-LOCAL_STATIC_LIBRARIES := \
-    libbootloader_message \
-    libotautil \
-    libbase \
-    liblog \
-    libfs_mgr \
-    libcutils
-LOCAL_CFLAGS := -Wall -Werror
-LOCAL_INIT_RC := uncrypt.rc
-
-include $(BUILD_EXECUTABLE)
diff --git a/update_verifier/Android.mk b/update_verifier/Android.mk
index 33c5fe9..0ff8854 100644
--- a/update_verifier/Android.mk
+++ b/update_verifier/Android.mk
@@ -22,6 +22,10 @@
     update_verifier.cpp
 
 LOCAL_MODULE := libupdate_verifier
+
+LOCAL_STATIC_LIBRARIES := \
+    libotautil
+
 LOCAL_SHARED_LIBRARIES := \
     libbase \
     libcutils \
@@ -54,7 +58,9 @@
 
 LOCAL_MODULE := update_verifier
 LOCAL_STATIC_LIBRARIES := \
-    libupdate_verifier
+    libupdate_verifier \
+    libotautil
+
 LOCAL_SHARED_LIBRARIES := \
     libbase \
     libcutils \
diff --git a/update_verifier/update_verifier.cpp b/update_verifier/update_verifier.cpp
index ba7b7ae..c5e154f 100644
--- a/update_verifier/update_verifier.cpp
+++ b/update_verifier/update_verifier.cpp
@@ -58,6 +58,8 @@
 #include <android/hardware/boot/1.0/IBootControl.h>
 #include <cutils/android_reboot.h>
 
+#include "otautil/rangeset.h"
+
 using android::sp;
 using android::hardware::boot::V1_0::IBootControl;
 using android::hardware::boot::V1_0::BoolResult;
@@ -129,42 +131,33 @@
   // followed by 'count' number comma separated integers. Every two integers reprensent a
   // block range with the first number included in range but second number not included.
   // For example '4,64536,65343,74149,74150' represents: [64536,65343) and [74149,74150).
-  std::vector<std::string> ranges = android::base::Split(range_str, ",");
-  size_t range_count;
-  bool status = android::base::ParseUint(ranges[0], &range_count);
-  if (!status || (range_count == 0) || (range_count % 2 != 0) ||
-      (range_count != ranges.size() - 1)) {
-    LOG(ERROR) << "Error in parsing range string.";
+  RangeSet ranges = RangeSet::Parse(range_str);
+  if (!ranges) {
+    LOG(ERROR) << "Error parsing RangeSet string " << range_str;
     return false;
   }
-  range_count /= 2;
+
+  // RangeSet::Split() splits the ranges into multiple groups with same number of blocks (except for
+  // the last group).
+  size_t thread_num = std::thread::hardware_concurrency() ?: 4;
+  std::vector<RangeSet> groups = ranges.Split(thread_num);
 
   std::vector<std::future<bool>> threads;
-  size_t thread_num = std::thread::hardware_concurrency() ?: 4;
-  thread_num = std::min(thread_num, range_count);
-  size_t group_range_count = (range_count + thread_num - 1) / thread_num;
-
-  for (size_t t = 0; t < thread_num; t++) {
-    auto thread_func = [t, group_range_count, &dm_block_device, &ranges, &partition]() {
-      size_t blk_count = 0;
-      static constexpr size_t kBlockSize = 4096;
-      std::vector<uint8_t> buf(1024 * kBlockSize);
+  for (const auto& group : groups) {
+    auto thread_func = [&group, &dm_block_device, &partition]() {
       android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
       if (fd.get() == -1) {
         PLOG(ERROR) << "Error reading " << dm_block_device << " for partition " << partition;
         return false;
       }
 
-      for (size_t i = group_range_count * 2 * t + 1;
-           i < std::min(group_range_count * 2 * (t + 1) + 1, ranges.size()); i += 2) {
-        unsigned int range_start, range_end;
-        bool parse_status = android::base::ParseUint(ranges[i], &range_start);
-        parse_status = parse_status && android::base::ParseUint(ranges[i + 1], &range_end);
-        if (!parse_status || range_start >= range_end) {
-          LOG(ERROR) << "Invalid range pair " << ranges[i] << ", " << ranges[i + 1];
-          return false;
-        }
+      static constexpr size_t kBlockSize = 4096;
+      std::vector<uint8_t> buf(1024 * kBlockSize);
 
+      size_t block_count = 0;
+      for (const auto& range : group) {
+        size_t range_start = range.first;
+        size_t range_end = range.second;
         if (lseek64(fd.get(), static_cast<off64_t>(range_start) * kBlockSize, SEEK_SET) == -1) {
           PLOG(ERROR) << "lseek to " << range_start << " failed";
           return false;
@@ -179,9 +172,9 @@
           }
           remain -= to_read;
         }
-        blk_count += (range_end - range_start);
+        block_count += (range_end - range_start);
       }
-      LOG(INFO) << "Finished reading " << blk_count << " blocks on " << dm_block_device;
+      LOG(INFO) << "Finished reading " << block_count << " blocks on " << dm_block_device;
       return true;
     };
 
diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index 1c931af..08f9930 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -1318,7 +1318,7 @@
 
       RangeSinkWriter writer(params.fd, tgt);
       if (params.cmdname[0] == 'i') {  // imgdiff
-        if (ApplyImagePatch(params.buffer.data(), blocks * BLOCKSIZE, &patch_value,
+        if (ApplyImagePatch(params.buffer.data(), blocks * BLOCKSIZE, patch_value,
                             std::bind(&RangeSinkWriter::Write, &writer, std::placeholders::_1,
                                       std::placeholders::_2),
                             nullptr, nullptr) != 0) {
@@ -1327,7 +1327,7 @@
           return -1;
         }
       } else {
-        if (ApplyBSDiffPatch(params.buffer.data(), blocks * BLOCKSIZE, &patch_value, 0,
+        if (ApplyBSDiffPatch(params.buffer.data(), blocks * BLOCKSIZE, patch_value, 0,
                              std::bind(&RangeSinkWriter::Write, &writer, std::placeholders::_1,
                                        std::placeholders::_2),
                              nullptr) != 0) {