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/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/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