diff --git a/README.md b/README.md
index dc3d44e..8e20b5a 100644
--- a/README.md
+++ b/README.md
@@ -40,3 +40,10 @@
 - Reboot the device immediately and run the test again. The test should save the
   contents of pmsg buffer into /data/misc/recovery/inject.txt. Test will pass if
   this file has expected contents.
+
+`ResourceTest` validates whether the png files are qualified as background text
+image under recovery.
+
+    1. `adb sync data` to make sure the test-dir has the images to test.
+    2. The test will automatically pickup and verify all `_text.png` files in
+       the test dir.
diff --git a/applypatch/Android.mk b/applypatch/Android.mk
index ec3c6ee..bdaef1b 100644
--- a/applypatch/Android.mk
+++ b/applypatch/Android.mk
@@ -35,7 +35,9 @@
     libcrypto \
     libbz \
     libz
-LOCAL_CFLAGS := -Werror
+LOCAL_CFLAGS := \
+    -DZLIB_CONST \
+    -Werror
 include $(BUILD_STATIC_LIBRARY)
 
 # libimgpatch (static library)
@@ -54,7 +56,9 @@
     libcrypto \
     libbz \
     libz
-LOCAL_CFLAGS := -Werror
+LOCAL_CFLAGS := \
+    -DZLIB_CONST \
+    -Werror
 include $(BUILD_STATIC_LIBRARY)
 
 # libimgpatch (host static library)
@@ -74,7 +78,9 @@
     libcrypto \
     libbz \
     libz
-LOCAL_CFLAGS := -Werror
+LOCAL_CFLAGS := \
+    -DZLIB_CONST \
+    -Werror
 include $(BUILD_HOST_STATIC_LIBRARY)
 
 # libapplypatch_modes (static library)
@@ -124,6 +130,8 @@
 
 libimgdiff_static_libraries := \
     libbsdiff \
+    libdivsufsort \
+    libdivsufsort64 \
     libbase \
     libz
 
@@ -166,7 +174,5 @@
 LOCAL_STATIC_LIBRARIES := \
     libimgdiff \
     $(libimgdiff_static_libraries) \
-    libbz \
-    libdivsufsort \
-    libdivsufsort64
+    libbz
 include $(BUILD_HOST_EXECUTABLE)
diff --git a/applypatch/imgdiff.cpp b/applypatch/imgdiff.cpp
index 62de726..3951506 100644
--- a/applypatch/imgdiff.cpp
+++ b/applypatch/imgdiff.cpp
@@ -615,12 +615,12 @@
 }
 
 /*
- * Given source and target chunks, compute a bsdiff patch between them
- * by running bsdiff in a subprocess.  Return the patch data, placing
- * its length in *size.  Return NULL on failure.  We expect the bsdiff
- * program to be in the path.
+ * Given source and target chunks, compute a bsdiff patch between them.
+ * Return the patch data, placing its length in *size. Return NULL on failure.
+ * |bsdiff_cache| can be used to cache the suffix array if the same |src| chunk
+ * is used repeatedly, pass nullptr if not needed.
  */
-unsigned char* MakePatch(ImageChunk* src, ImageChunk* tgt, size_t* size) {
+unsigned char* MakePatch(ImageChunk* src, ImageChunk* tgt, size_t* size, saidx_t** bsdiff_cache) {
   if (tgt->type == CHUNK_NORMAL) {
     if (tgt->len <= 160) {
       tgt->type = CHUNK_RAW;
@@ -644,7 +644,7 @@
   close(fd); // temporary file is created and we don't need its file
              // descriptor
 
-  int r = bsdiff::bsdiff(src->data, src->len, tgt->data, tgt->len, ptemp);
+  int r = bsdiff::bsdiff(src->data, src->len, tgt->data, tgt->len, ptemp, bsdiff_cache);
   if (r != 0) {
     printf("bsdiff() failed: %d\n", r);
     return NULL;
@@ -970,28 +970,31 @@
   unsigned char** patch_data = static_cast<unsigned char**>(malloc(
       num_tgt_chunks * sizeof(unsigned char*)));
   size_t* patch_size = static_cast<size_t*>(malloc(num_tgt_chunks * sizeof(size_t)));
+  saidx_t* bsdiff_cache = nullptr;
   for (i = 0; i < num_tgt_chunks; ++i) {
     if (zip_mode) {
       ImageChunk* src;
       if (tgt_chunks[i].type == CHUNK_DEFLATE &&
           (src = FindChunkByName(tgt_chunks[i].filename, src_chunks, num_src_chunks))) {
-        patch_data[i] = MakePatch(src, tgt_chunks+i, patch_size+i);
+        patch_data[i] = MakePatch(src, tgt_chunks + i, patch_size + i, nullptr);
       } else {
-        patch_data[i] = MakePatch(src_chunks, tgt_chunks+i, patch_size+i);
+        patch_data[i] = MakePatch(src_chunks, tgt_chunks + i, patch_size + i, &bsdiff_cache);
       }
     } else {
       if (i == 1 && bonus_data) {
         printf("  using %zu bytes of bonus data for chunk %d\n", bonus_size, i);
-        src_chunks[i].data = static_cast<unsigned char*>(realloc(src_chunks[i].data,
-            src_chunks[i].len + bonus_size));
-        memcpy(src_chunks[i].data+src_chunks[i].len, bonus_data, bonus_size);
+        src_chunks[i].data =
+            static_cast<unsigned char*>(realloc(src_chunks[i].data, src_chunks[i].len + bonus_size));
+        memcpy(src_chunks[i].data + src_chunks[i].len, bonus_data, bonus_size);
         src_chunks[i].len += bonus_size;
-     }
+      }
 
-      patch_data[i] = MakePatch(src_chunks+i, tgt_chunks+i, patch_size+i);
+      patch_data[i] = MakePatch(src_chunks + i, tgt_chunks + i, patch_size + i, nullptr);
     }
     printf("patch %3d is %zu bytes (of %zu)\n", i, patch_size[i], tgt_chunks[i].source_len);
   }
+  free(bsdiff_cache);
+  free(src_chunks);
 
   // Figure out how big the imgdiff file header is going to be, so
   // that we can correctly compute the offset of each bsdiff patch
@@ -1068,6 +1071,7 @@
     }
   }
 
+  free(tgt_chunks);
   free(patch_data);
   free(patch_size);
 
diff --git a/applypatch/imgpatch.cpp b/applypatch/imgpatch.cpp
index ae6071f..00ea90e 100644
--- a/applypatch/imgpatch.cpp
+++ b/applypatch/imgpatch.cpp
@@ -160,7 +160,7 @@
         strm.zfree = Z_NULL;
         strm.opaque = Z_NULL;
         strm.avail_in = src_len;
-        strm.next_in = const_cast<unsigned char*>(old_data + src_start);
+        strm.next_in = old_data + src_start;
         strm.avail_out = expanded_len;
         strm.next_out = expanded_source.data();
 
diff --git a/install.cpp b/install.cpp
index d3ab213..959a742 100644
--- a/install.cpp
+++ b/install.cpp
@@ -420,11 +420,7 @@
         LOG(ERROR) << "invalid \"set_progress\" parameters: " << line;
       }
     } else if (command == "ui_print") {
-      if (!args.empty()) {
-        ui->PrintOnScreenOnly("%s", args.c_str());
-      } else {
-        ui->PrintOnScreenOnly("\n");
-      }
+      ui->PrintOnScreenOnly("%s\n", args.c_str());
       fflush(stdout);
     } else if (command == "wipe_cache") {
       *wipe_cache = true;
diff --git a/minui/resources.cpp b/minui/resources.cpp
index 9c69030..c0f9c5c 100644
--- a/minui/resources.cpp
+++ b/minui/resources.cpp
@@ -372,7 +372,9 @@
 // This function tests if a locale string stored in PNG (prefix) matches
 // the locale string provided by the system (locale).
 bool matches_locale(const char* prefix, const char* locale) {
-    if (locale == NULL) return false;
+    if (locale == nullptr) {
+        return false;
+    }
 
     // Return true if the whole string of prefix matches the top part of
     // locale. For instance, prefix == "en" matches locale == "en_US";
diff --git a/res-xxhdpi/images/erasing_text.png b/res-xxhdpi/images/erasing_text.png
index 8e8dfc4..86693f4 100644
--- a/res-xxhdpi/images/erasing_text.png
+++ b/res-xxhdpi/images/erasing_text.png
Binary files differ
diff --git a/res-xxhdpi/images/error_text.png b/res-xxhdpi/images/error_text.png
index 7fd1983..9c4bcab 100644
--- a/res-xxhdpi/images/error_text.png
+++ b/res-xxhdpi/images/error_text.png
Binary files differ
diff --git a/res-xxhdpi/images/installing_security_text.png b/res-xxhdpi/images/installing_security_text.png
index 9779927..f5ec698 100644
--- a/res-xxhdpi/images/installing_security_text.png
+++ b/res-xxhdpi/images/installing_security_text.png
Binary files differ
diff --git a/res-xxhdpi/images/installing_text.png b/res-xxhdpi/images/installing_text.png
index fa48896..100a5b3 100644
--- a/res-xxhdpi/images/installing_text.png
+++ b/res-xxhdpi/images/installing_text.png
Binary files differ
diff --git a/res-xxhdpi/images/no_command_text.png b/res-xxhdpi/images/no_command_text.png
index d72a840..590030c 100644
--- a/res-xxhdpi/images/no_command_text.png
+++ b/res-xxhdpi/images/no_command_text.png
Binary files differ
diff --git a/res-xxxhdpi/images/erasing_text.png b/res-xxxhdpi/images/erasing_text.png
index 7c19817..4cf5d76 100644
--- a/res-xxxhdpi/images/erasing_text.png
+++ b/res-xxxhdpi/images/erasing_text.png
Binary files differ
diff --git a/res-xxxhdpi/images/error_text.png b/res-xxxhdpi/images/error_text.png
index 4cd2a8c..8dd6f12 100644
--- a/res-xxxhdpi/images/error_text.png
+++ b/res-xxxhdpi/images/error_text.png
Binary files differ
diff --git a/res-xxxhdpi/images/installing_security_text.png b/res-xxxhdpi/images/installing_security_text.png
index d84c5d9..fa06f31 100644
--- a/res-xxxhdpi/images/installing_security_text.png
+++ b/res-xxxhdpi/images/installing_security_text.png
Binary files differ
diff --git a/res-xxxhdpi/images/installing_text.png b/res-xxxhdpi/images/installing_text.png
index ffe1474..d0f9301 100644
--- a/res-xxxhdpi/images/installing_text.png
+++ b/res-xxxhdpi/images/installing_text.png
Binary files differ
diff --git a/res-xxxhdpi/images/no_command_text.png b/res-xxxhdpi/images/no_command_text.png
index f4f1300..233aec4 100644
--- a/res-xxxhdpi/images/no_command_text.png
+++ b/res-xxxhdpi/images/no_command_text.png
Binary files differ
diff --git a/tests/Android.mk b/tests/Android.mk
index 1203817..1dbd2b6 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -49,10 +49,34 @@
 LOCAL_CFLAGS := -Werror
 LOCAL_MODULE := recovery_manual_test
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
-LOCAL_STATIC_LIBRARIES := libbase
+LOCAL_STATIC_LIBRARIES := \
+    libminui \
+    libbase
 
 LOCAL_SRC_FILES := manual/recovery_test.cpp
-LOCAL_SHARED_LIBRARIES := liblog
+LOCAL_SHARED_LIBRARIES := \
+    liblog \
+    libpng
+
+resource_files := $(call find-files-in-subdirs, bootable/recovery, \
+    "*_text.png", \
+    res-mdpi/images \
+    res-hdpi/images \
+    res-xhdpi/images \
+    res-xxhdpi/images \
+    res-xxxhdpi/images \
+    )
+
+# The resource image files that will go to $OUT/data/nativetest/recovery.
+testimage_out_path := $(TARGET_OUT_DATA)/nativetest/recovery
+GEN := $(addprefix $(testimage_out_path)/, $(resource_files))
+
+$(GEN): PRIVATE_PATH := $(LOCAL_PATH)
+$(GEN): PRIVATE_CUSTOM_TOOL = cp $< $@
+$(GEN): $(testimage_out_path)/% : bootable/recovery/%
+	$(transform-generated-source)
+LOCAL_GENERATED_SOURCES += $(GEN)
+
 include $(BUILD_NATIVE_TEST)
 
 # Component tests
diff --git a/tests/manual/recovery_test.cpp b/tests/manual/recovery_test.cpp
index e73cb15..d36dd33 100644
--- a/tests/manual/recovery_test.cpp
+++ b/tests/manual/recovery_test.cpp
@@ -14,19 +14,27 @@
  * limitations under the License.
  */
 
+#include <dirent.h>
 #include <string.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include <string>
+#include <vector>
 
 #include <android-base/file.h>
+#include <android-base/strings.h>
 #include <android/log.h>
 #include <gtest/gtest.h>
+#include <png.h>
 #include <private/android_logger.h>
 
+#include "minui/minui.h"
+
 static const std::string myFilename = "/data/misc/recovery/inject.txt";
 static const std::string myContent = "Hello World\nWelcome to my recovery\n";
+static const std::string kLocale = "zu";
+static const std::string kResourceTestDir = "/data/nativetest/recovery/";
 
 // Failure is expected on systems that do not deliver either the
 // recovery-persist or recovery-refresh executables. Tests also require
@@ -84,3 +92,133 @@
   }
   EXPECT_EQ(0, unlink(myFilename.c_str()));
 }
+
+std::vector<std::string> image_dir {
+  "res-mdpi/images/",
+  "res-hdpi/images/",
+  "res-xhdpi/images/",
+  "res-xxhdpi/images/",
+  "res-xxxhdpi/images/"
+};
+
+static int png_filter(const dirent* de) {
+  if (de->d_type != DT_REG || !android::base::EndsWith(de->d_name, "_text.png")) {
+    return 0;
+  }
+  return 1;
+}
+
+// Find out all png files to test under /data/nativetest/recovery/.
+static std::vector<std::string> add_files() {
+  std::vector<std::string> files;
+  for (const std::string& str : image_dir) {
+    std::string dir_path = kResourceTestDir + str;
+    dirent** namelist;
+    int n = scandir(dir_path.c_str(), &namelist, png_filter, alphasort);
+    if (n == -1) {
+      printf("Failed to scan dir %s: %s\n", kResourceTestDir.c_str(), strerror(errno));
+      return files;
+    }
+    if (n == 0) {
+      printf("No file is added for test in %s\n", kResourceTestDir.c_str());
+    }
+
+    while (n--) {
+      std::string file_path = dir_path + namelist[n]->d_name;
+      files.push_back(file_path);
+      free(namelist[n]);
+    }
+    free(namelist);
+  }
+  return files;
+}
+
+class ResourceTest : public testing::TestWithParam<std::string> {
+ public:
+  static std::vector<std::string> png_list;
+
+  // Parse a png file and test if it's qualified for the background text image
+  // under recovery.
+  void SetUp() override {
+    std::string file_path = GetParam();
+    fp = fopen(file_path.c_str(), "rb");
+    ASSERT_NE(nullptr, fp);
+
+    unsigned char header[8];
+    size_t bytesRead = fread(header, 1, sizeof(header), fp);
+    ASSERT_EQ(sizeof(header), bytesRead);
+    ASSERT_EQ(0, png_sig_cmp(header, 0, sizeof(header)));
+
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
+    ASSERT_NE(nullptr, png_ptr);
+
+    info_ptr = png_create_info_struct(png_ptr);
+    ASSERT_NE(nullptr, info_ptr);
+
+    png_init_io(png_ptr, fp);
+    png_set_sig_bytes(png_ptr, sizeof(header));
+    png_read_info(png_ptr, info_ptr);
+
+    int color_type, bit_depth;
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, nullptr, nullptr,
+                 nullptr);
+    ASSERT_EQ(PNG_COLOR_TYPE_GRAY, color_type) << "Recovery expects grayscale PNG file.";
+    ASSERT_LT(static_cast<png_uint_32>(5), width);
+    ASSERT_LT(static_cast<png_uint_32>(0), height);
+    if (bit_depth <= 8) {
+      // 1-, 2-, 4-, or 8-bit gray images: expand to 8-bit gray.
+      png_set_expand_gray_1_2_4_to_8(png_ptr);
+    }
+
+    png_byte channels = png_get_channels(png_ptr, info_ptr);
+    ASSERT_EQ(1, channels) << "Recovery background text images expects 1-channel PNG file.";
+  }
+
+  void TearDown() override {
+    if (png_ptr != nullptr && info_ptr != nullptr) {
+      png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
+    }
+
+    if (fp != nullptr) {
+      fclose(fp);
+    }
+  }
+
+ protected:
+  png_structp png_ptr;
+  png_infop info_ptr;
+  png_uint_32 width, height;
+
+  FILE* fp;
+};
+
+std::vector<std::string> ResourceTest::png_list = add_files();
+
+TEST_P(ResourceTest, ValidateLocale) {
+  std::vector<unsigned char> row(width);
+  for (png_uint_32 y = 0; y < height; ++y) {
+    png_read_row(png_ptr, row.data(), nullptr);
+    int w = (row[1] << 8) | row[0];
+    int h = (row[3] << 8) | row[2];
+    int len = row[4];
+    EXPECT_LT(0, w);
+    EXPECT_LT(0, h);
+    EXPECT_LT(0, len) << "Locale string should be non-empty.";
+    EXPECT_NE(0, row[5]) << "Locale string is missing.";
+
+    ASSERT_GT(height, y + 1 + h) << "Locale: " << kLocale << " is not found in the file.";
+    char* loc = reinterpret_cast<char*>(&row[5]);
+    if (matches_locale(loc, kLocale.c_str())) {
+      EXPECT_TRUE(android::base::StartsWith(loc, kLocale.c_str()));
+      break;
+    } else {
+      for (int i = 0; i < h; ++i, ++y) {
+        png_read_row(png_ptr, row.data(), nullptr);
+      }
+    }
+  }
+}
+
+INSTANTIATE_TEST_CASE_P(BackgroundTextValidation, ResourceTest,
+                        ::testing::ValuesIn(ResourceTest::png_list.cbegin(),
+                                            ResourceTest::png_list.cend()));
diff --git a/tests/unit/locale_test.cpp b/tests/unit/locale_test.cpp
index 0e515f8..f732350 100644
--- a/tests/unit/locale_test.cpp
+++ b/tests/unit/locale_test.cpp
@@ -26,4 +26,7 @@
     EXPECT_TRUE(matches_locale("en", "en_GB"));
     EXPECT_FALSE(matches_locale("en_GB", "en"));
     EXPECT_FALSE(matches_locale("en_GB", "en_US"));
+    EXPECT_FALSE(matches_locale("en_US", ""));
+    // Empty locale prefix in the PNG file will match the input locale.
+    EXPECT_TRUE(matches_locale("", "en_US"));
 }
diff --git a/tools/recovery_l10n/README.md b/tools/recovery_l10n/README.md
index 1554f66..e9e85d6 100644
--- a/tools/recovery_l10n/README.md
+++ b/tools/recovery_l10n/README.md
@@ -8,6 +8,9 @@
 
     *   For example, we can use Nexus 5 to generate the text images under
         res-xxhdpi.
+    *   We can set up the maximum width of the final png image in res/layout/main.xml
+        Currently, the image width is 1200px for xxxhdpi, 900px for xxhdpi and
+        480px for xhdpi/hdpi/mdpi.
     *   When using the emulator, make sure the NDK version matches the current
         repository. Otherwise, the app may not work properly.
 
diff --git a/update_verifier/update_verifier.cpp b/update_verifier/update_verifier.cpp
index e97a3ad..1c9be2d 100644
--- a/update_verifier/update_verifier.cpp
+++ b/update_verifier/update_verifier.cpp
@@ -28,7 +28,6 @@
  *
  * The current slot will be marked as having booted successfully if the
  * verifier reaches the end after the verification.
- *
  */
 
 #include <errno.h>
@@ -42,9 +41,9 @@
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
+#include <android-base/properties.h>
 #include <android-base/strings.h>
 #include <android-base/unique_fd.h>
-#include <cutils/properties.h>
 #include <android/hardware/boot/1.0/IBootControl.h>
 
 using android::sp;
@@ -56,54 +55,53 @@
 constexpr int BLOCKSIZE = 4096;
 
 static bool read_blocks(const std::string& blk_device_prefix, const std::string& range_str) {
-    char slot_suffix[PROPERTY_VALUE_MAX];
-    property_get("ro.boot.slot_suffix", slot_suffix, "");
-    std::string blk_device = blk_device_prefix + std::string(slot_suffix);
-    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(blk_device.c_str(), O_RDONLY)));
-    if (fd.get() == -1) {
-        PLOG(ERROR) << "Error reading partition " << blk_device;
-        return false;
+  std::string slot_suffix = android::base::GetProperty("ro.boot.slot_suffix", "");
+  std::string blk_device = blk_device_prefix + slot_suffix;
+  android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(blk_device.c_str(), O_RDONLY)));
+  if (fd.get() == -1) {
+    PLOG(ERROR) << "Error reading partition " << blk_device;
+    return false;
+  }
+
+  // For block range string, first integer 'count' equals 2 * total number of valid ranges,
+  // 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.";
+    return false;
+  }
+
+  size_t blk_count = 0;
+  for (size_t i = 1; i < 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;
     }
 
-    // For block range string, first integer 'count' equals 2 * total number of valid ranges,
-    // 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].c_str(), &range_count);
-    if (!status || (range_count == 0) || (range_count % 2 != 0) ||
-            (range_count != ranges.size()-1)) {
-        LOG(ERROR) << "Error in parsing range string.";
-        return false;
+    if (lseek64(fd.get(), static_cast<off64_t>(range_start) * BLOCKSIZE, SEEK_SET) == -1) {
+      PLOG(ERROR) << "lseek to " << range_start << " failed";
+      return false;
     }
 
-    size_t blk_count = 0;
-    for (size_t i = 1; i < ranges.size(); i += 2) {
-        unsigned int range_start, range_end;
-        bool parse_status = android::base::ParseUint(ranges[i].c_str(), &range_start);
-        parse_status = parse_status && android::base::ParseUint(ranges[i+1].c_str(), &range_end);
-        if (!parse_status || range_start >= range_end) {
-            LOG(ERROR) << "Invalid range pair " << ranges[i] << ", " << ranges[i+1];
-            return false;
-        }
-
-        if (lseek64(fd.get(), static_cast<off64_t>(range_start) * BLOCKSIZE, SEEK_SET) == -1) {
-            PLOG(ERROR) << "lseek to " << range_start << " failed";
-            return false;
-        }
-
-        size_t size = (range_end - range_start) * BLOCKSIZE;
-        std::vector<uint8_t> buf(size);
-        if (!android::base::ReadFully(fd.get(), buf.data(), size)) {
-            PLOG(ERROR) << "Failed to read blocks " << range_start << " to " << range_end;
-            return false;
-        }
-        blk_count += (range_end - range_start);
+    size_t size = (range_end - range_start) * BLOCKSIZE;
+    std::vector<uint8_t> buf(size);
+    if (!android::base::ReadFully(fd.get(), buf.data(), size)) {
+      PLOG(ERROR) << "Failed to read blocks " << range_start << " to " << range_end;
+      return false;
     }
+    blk_count += (range_end - range_start);
+  }
 
-    LOG(INFO) << "Finished reading " << blk_count << " blocks on " << blk_device;
-    return true;
+  LOG(INFO) << "Finished reading " << blk_count << " blocks on " << blk_device;
+  return true;
 }
 
 static bool verify_image(const std::string& care_map_name) {
@@ -147,7 +145,7 @@
     LOG(INFO) << "Started with arg " << i << ": " << argv[i];
   }
 
-  sp<IBootControl> module = IBootControl::getService("bootctrl");
+  sp<IBootControl> module = IBootControl::getService();
   if (module == nullptr) {
     LOG(ERROR) << "Error getting bootctrl module.";
     return -1;
@@ -160,16 +158,16 @@
 
   if (is_successful == BoolResult::FALSE) {
     // The current slot has not booted successfully.
-    char verity_mode[PROPERTY_VALUE_MAX];
-    if (property_get("ro.boot.veritymode", verity_mode, "") == -1) {
+    std::string verity_mode = android::base::GetProperty("ro.boot.veritymode", "");
+    if (verity_mode.empty()) {
       LOG(ERROR) << "Failed to get dm-verity mode.";
       return -1;
-    } else if (strcasecmp(verity_mode, "eio") == 0) {
+    } else if (android::base::EqualsIgnoreCase(verity_mode, "eio")) {
       // We shouldn't see verity in EIO mode if the current slot hasn't booted
       // successfully before. Therefore, fail the verification when veritymode=eio.
       LOG(ERROR) << "Found dm-verity in EIO mode, skip verification.";
       return -1;
-    } else if (strcmp(verity_mode, "enforcing") != 0) {
+    } else if (verity_mode != "enforcing") {
       LOG(ERROR) << "Unexpected dm-verity mode : " << verity_mode << ", expecting enforcing.";
       return -1;
     } else if (!verify_image(CARE_MAP_FILE)) {
diff --git a/updater/install.cpp b/updater/install.cpp
index 6431454..7a8e92f 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -76,7 +76,6 @@
   for (auto& line : lines) {
     if (!line.empty()) {
       fprintf(ui->cmd_pipe, "ui_print %s\n", line.c_str());
-      fprintf(ui->cmd_pipe, "ui_print\n");
     }
   }
 
diff --git a/updater/updater.cpp b/updater/updater.cpp
index 4730662..22c060f 100644
--- a/updater/updater.cpp
+++ b/updater/updater.cpp
@@ -191,7 +191,6 @@
         }
         fprintf(cmd_pipe, "ui_print %s\n", line.c_str());
       }
-      fprintf(cmd_pipe, "ui_print\n");
     }
 
     if (state.error_code != kNoError) {