diff --git a/core/android_manifest.mk b/core/android_manifest.mk
index 8fab9c6..254e09b 100644
--- a/core/android_manifest.mk
+++ b/core/android_manifest.mk
@@ -45,7 +45,7 @@
 my_min_sdk_version := $(call module-min-sdk-version)
 
 ifdef TARGET_BUILD_APPS
-  ifndef TARGET_BUILD_APPS_USE_PREBUILT_SDK
+  ifndef TARGET_BUILD_USE_PREBUILT_SDKS
     ifeq ($(my_target_sdk_version),$(PLATFORM_VERSION_CODENAME))
       ifdef UNBUNDLED_BUILD_TARGET_SDK_WITH_API_FINGERPRINT
         my_target_sdk_version := $(my_target_sdk_version).$$(cat $(API_FINGERPRINT))
diff --git a/core/base_rules.mk b/core/base_rules.mk
index abe059b..71c0d73 100644
--- a/core/base_rules.mk
+++ b/core/base_rules.mk
@@ -77,20 +77,6 @@
 endif
 _path :=
 
-ifeq ($(LOCAL_HOST_MODULE),true)
-my_image_variant := host
-else ifeq ($(LOCAL_VENDOR_MODULE),true)
-my_image_variant := vendor
-else ifeq ($(LOCAL_OEM_MODULE),true)
-my_image_variant := vendor
-else ifeq ($(LOCAL_ODM_MODULE),true)
-my_image_variant := vendor
-else ifeq ($(LOCAL_PRODUCT_MODULE),true)
-my_image_variant := product
-else
-my_image_variant := core
-endif
-
 # TODO(b/135957588) Remove following workaround
 # LOCAL_PRODUCT_SERVICES_MODULE to LOCAL_PRODUCT_MODULE for all Android.mk
 ifndef LOCAL_PRODUCT_MODULE
@@ -107,6 +93,20 @@
 $(call pretty-error,Only one of LOCAL_PROPRIETARY_MODULE[$(LOCAL_PROPRIETARY_MODULE)] and LOCAL_VENDOR_MODULE[$(LOCAL_VENDOR_MODULE)] may be set, or they must be equal)
 endif
 
+ifeq ($(LOCAL_HOST_MODULE),true)
+my_image_variant := host
+else ifeq ($(LOCAL_VENDOR_MODULE),true)
+my_image_variant := vendor
+else ifeq ($(LOCAL_OEM_MODULE),true)
+my_image_variant := vendor
+else ifeq ($(LOCAL_ODM_MODULE),true)
+my_image_variant := vendor
+else ifeq ($(LOCAL_PRODUCT_MODULE),true)
+my_image_variant := product
+else
+my_image_variant := core
+endif
+
 non_system_module := $(filter true, \
    $(LOCAL_PRODUCT_MODULE) \
    $(LOCAL_SYSTEM_EXT_MODULE) \
diff --git a/core/config.mk b/core/config.mk
index a35b718..1a0a418 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -517,18 +517,27 @@
 ifeq ($(TARGET_BUILD_PDK),true)
 ALLOW_MISSING_DEPENDENCIES := true
 endif
+ifeq ($(TARGET_BUILD_UNBUNDLED_IMAGE),true)
+ALLOW_MISSING_DEPENDENCIES := true
+endif
 ifneq ($(filter true,$(SOONG_ALLOW_MISSING_DEPENDENCIES)),)
 ALLOW_MISSING_DEPENDENCIES := true
 endif
 .KATI_READONLY := ALLOW_MISSING_DEPENDENCIES
 
-TARGET_BUILD_APPS_USE_PREBUILT_SDK :=
-ifdef TARGET_BUILD_APPS
+TARGET_BUILD_USE_PREBUILT_SDKS :=
+DISABLE_PREOPT :=
+ifneq (,$(TARGET_BUILD_APPS)$(TARGET_BUILD_UNBUNDLED_IMAGE))
+  DISABLE_PREOPT := true
   ifndef UNBUNDLED_BUILD_SDKS_FROM_SOURCE
-    TARGET_BUILD_APPS_USE_PREBUILT_SDK := true
+    TARGET_BUILD_USE_PREBUILT_SDKS := true
   endif
 endif
 
+.KATI_READONLY := \
+  TARGET_BUILD_USE_PREBUILT_SDKS \
+  DISABLE_PREOPT \
+
 prebuilt_sdk_tools := prebuilts/sdk/tools
 prebuilt_sdk_tools_bin := $(prebuilt_sdk_tools)/$(HOST_OS)/bin
 
@@ -550,18 +559,18 @@
 .KATI_READONLY := USE_D8
 
 #
-# Tools that are prebuilts for TARGET_BUILD_APPS
+# Tools that are prebuilts for TARGET_BUILD_USE_PREBUILT_SDKS
 #
-ifeq (,$(TARGET_BUILD_APPS)$(filter true,$(TARGET_BUILD_PDK)))
+ifeq (,$(TARGET_BUILD_USE_PREBUILT_SDKS)$(filter true,$(TARGET_BUILD_PDK)))
   AAPT := $(HOST_OUT_EXECUTABLES)/aapt
   MAINDEXCLASSES := $(HOST_OUT_EXECUTABLES)/mainDexClasses
 
-else # TARGET_BUILD_APPS || TARGET_BUILD_PDK
+else # TARGET_BUILD_USE_PREBUILT_SDKS || TARGET_BUILD_PDK
   AAPT := $(prebuilt_sdk_tools_bin)/aapt
   MAINDEXCLASSES := $(prebuilt_sdk_tools)/mainDexClasses
-endif # TARGET_BUILD_APPS || TARGET_BUILD_PDK
+endif # TARGET_BUILD_USE_PREBUILT_SDKS || TARGET_BUILD_PDK
 
-ifeq (,$(TARGET_BUILD_APPS))
+ifeq (,$(TARGET_BUILD_USE_PREBUILT_SDKS))
   # Use RenderScript prebuilts for unbundled builds but not PDK builds
   LLVM_RS_CC := $(HOST_OUT_EXECUTABLES)/llvm-rs-cc
   BCC_COMPAT := $(HOST_OUT_EXECUTABLES)/bcc_compat
@@ -1109,7 +1118,7 @@
 HISTORICAL_NDK_VERSIONS_ROOT := $(TOPDIR)prebuilts/ndk
 
 # The path where app can reference the support library resources.
-ifdef TARGET_BUILD_APPS
+ifdef TARGET_BUILD_USE_PREBUILT_SDKS
 SUPPORT_LIBRARY_ROOT := $(HISTORICAL_SDK_VERSIONS_ROOT)/current/support
 else
 SUPPORT_LIBRARY_ROOT := frameworks/support
diff --git a/core/dex_preopt_config.mk b/core/dex_preopt_config.mk
index 55f6f0b..41a2be9 100644
--- a/core/dex_preopt_config.mk
+++ b/core/dex_preopt_config.mk
@@ -5,7 +5,7 @@
   ENABLE_PREOPT :=
 else ifneq (true,$(filter true,$(PRODUCT_USES_DEFAULT_ART_CONFIG)))
   ENABLE_PREOPT :=
-else ifneq (,$(TARGET_BUILD_APPS))
+else ifeq (true,$(DISABLE_PREOPT))
   ENABLE_PREOPT :=
 endif
 
diff --git a/core/dex_preopt_odex_install.mk b/core/dex_preopt_odex_install.mk
index 3d5f68a..799b623 100644
--- a/core/dex_preopt_odex_install.mk
+++ b/core/dex_preopt_odex_install.mk
@@ -40,8 +40,8 @@
   LOCAL_DEX_PREOPT :=
 endif
 
-# Disable preopt for TARGET_BUILD_APPS
-ifneq (,$(TARGET_BUILD_APPS))
+# Disable preopt for DISABLE_PREOPT
+ifeq (true,$(DISABLE_PREOPT))
   LOCAL_DEX_PREOPT :=
 endif
 
diff --git a/core/envsetup.mk b/core/envsetup.mk
index f78ecb4..167fed9 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -93,6 +93,7 @@
 endif
 
 TARGET_BUILD_APPS ?=
+TARGET_BUILD_UNBUNDLED_IMAGE ?=
 
 # Set to true for an unbundled build, i.e. a build without
 # support for platform targets like the system image. This also
@@ -107,11 +108,19 @@
   TARGET_BUILD_UNBUNDLED := true
 endif
 
+# TARGET_BUILD_UNBUNDLED_IMAGE also implies unbundled build.
+# (i.e. it targets to only unbundled image, such as the vendor image,
+# ,or the product image). 
+ifneq ($(TARGET_BUILD_UNBUNDLED_IMAGE),)
+  TARGET_BUILD_UNBUNDLED := true
+endif
+
 .KATI_READONLY := \
   TARGET_PRODUCT \
   TARGET_BUILD_VARIANT \
   TARGET_BUILD_APPS \
   TARGET_BUILD_UNBUNDLED \
+  TARGET_BUILD_UNBUNDLED_IMAGE \
 
 # ---------------------------------------------------------------
 # Set up configuration for host machine.  We don't do cross-
diff --git a/core/java.mk b/core/java.mk
index 2f18ad9..bb4593d 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -106,8 +106,8 @@
 
 aidl_preprocess_import :=
 ifdef LOCAL_SDK_VERSION
-ifneq ($(filter current system_current test_current core_current, $(LOCAL_SDK_VERSION)$(TARGET_BUILD_APPS_USE_PREBUILT_SDK)),)
-  # LOCAL_SDK_VERSION is current and no TARGET_BUILD_APPS
+ifneq ($(filter current system_current test_current core_current, $(LOCAL_SDK_VERSION)$(TARGET_BUILD_USE_PREBUILT_SDKS)),)
+  # LOCAL_SDK_VERSION is current and no TARGET_BUILD_USE_PREBUILT_SDKS
   aidl_preprocess_import := $(FRAMEWORK_AIDL)
 else
   aidl_preprocess_import := $(call resolve-prebuilt-sdk-aidl-path,$(LOCAL_SDK_VERSION))
diff --git a/core/java_common.mk b/core/java_common.mk
index b7f2883..1798ca8 100644
--- a/core/java_common.mk
+++ b/core/java_common.mk
@@ -25,7 +25,7 @@
     LOCAL_JAVA_LANGUAGE_VERSION := 1.7
   else ifneq (,$(filter $(LOCAL_SDK_VERSION), $(TARGET_SDK_VERSIONS_WITHOUT_JAVA_19_SUPPORT)))
     LOCAL_JAVA_LANGUAGE_VERSION := 1.8
-  else ifneq (,$(LOCAL_SDK_VERSION)$(TARGET_BUILD_APPS_USE_PREBUILT_SDK))
+  else ifneq (,$(LOCAL_SDK_VERSION)$(TARGET_BUILD_USE_PREBUILT_SDKS))
     # TODO(ccross): allow 1.9 for current and unbundled once we have SDK system modules
     LOCAL_JAVA_LANGUAGE_VERSION := 1.8
   else
@@ -268,7 +268,7 @@
       my_system_modules := $(LEGACY_CORE_PLATFORM_SYSTEM_MODULES)
     endif  # LOCAL_NO_STANDARD_LIBRARIES
 
-    ifneq (,$(TARGET_BUILD_APPS_USE_PREBUILT_SDK))
+    ifneq (,$(TARGET_BUILD_USE_PREBUILT_SDKS))
       sdk_libs := $(foreach lib_name,$(LOCAL_SDK_LIBRARIES),$(call resolve-prebuilt-sdk-module,system_current,$(lib_name)))
     else
       # When SDK libraries are referenced from modules built without SDK, provide the all APIs to them
@@ -283,8 +283,8 @@
              Choices are: $(TARGET_AVAILABLE_SDK_VERSIONS))
     endif
 
-    ifneq (,$(TARGET_BUILD_APPS_USE_PREBUILT_SDK)$(filter-out %current,$(LOCAL_SDK_VERSION)))
-      # TARGET_BUILD_APPS mode or numbered SDK. Use prebuilt modules.
+    ifneq (,$(TARGET_BUILD_USE_PREBUILT_SDKS)$(filter-out %current,$(LOCAL_SDK_VERSION)))
+      # TARGET_BUILD_USE_PREBUILT_SDKS mode or numbered SDK. Use prebuilt modules.
       sdk_module := $(call resolve-prebuilt-sdk-module,$(LOCAL_SDK_VERSION))
       sdk_libs := $(foreach lib_name,$(LOCAL_SDK_LIBRARIES),$(call resolve-prebuilt-sdk-module,$(LOCAL_SDK_VERSION),$(lib_name)))
     else
@@ -325,7 +325,7 @@
   # related classes to be present. This change adds stubs needed for
   # javac to compile lambdas.
   ifneq ($(LOCAL_NO_STANDARD_LIBRARIES),true)
-    ifdef TARGET_BUILD_APPS_USE_PREBUILT_SDK
+    ifdef TARGET_BUILD_USE_PREBUILT_SDKS
       full_java_bootclasspath_libs += $(call java-lib-header-files,sdk-core-lambda-stubs)
     else
       full_java_bootclasspath_libs += $(call java-lib-header-files,core-lambda-stubs)
diff --git a/core/java_prebuilt_internal.mk b/core/java_prebuilt_internal.mk
index 6ee1ae1..279b0e4 100644
--- a/core/java_prebuilt_internal.mk
+++ b/core/java_prebuilt_internal.mk
@@ -173,7 +173,7 @@
 framework_res_package_export :=
 # Please refer to package.mk
 ifneq ($(LOCAL_NO_STANDARD_LIBRARIES),true)
-ifneq ($(filter-out current system_current test_current,$(LOCAL_SDK_RES_VERSION))$(if $(TARGET_BUILD_APPS),$(filter current system_current test_current,$(LOCAL_SDK_RES_VERSION))),)
+ifneq ($(filter-out current system_current test_current,$(LOCAL_SDK_RES_VERSION))$(if $(TARGET_BUILD_USE_PREBUILT_SDKS),$(filter current system_current test_current,$(LOCAL_SDK_RES_VERSION))),)
 framework_res_package_export := \
     $(call resolve-prebuilt-sdk-jar-path,$(LOCAL_SDK_RES_VERSION))
 else
diff --git a/core/java_renderscript.mk b/core/java_renderscript.mk
index bfcf59e..572d6e4 100644
--- a/core/java_renderscript.mk
+++ b/core/java_renderscript.mk
@@ -50,8 +50,8 @@
 renderscript_flags += $(LOCAL_RENDERSCRIPT_FLAGS)
 
 # prepend the RenderScript system include path
-ifneq ($(filter-out current system_current test_current core_current,$(LOCAL_SDK_VERSION))$(if $(TARGET_BUILD_APPS),$(filter current system_current test_current,$(LOCAL_SDK_VERSION))),)
-# if a numeric LOCAL_SDK_VERSION, or current LOCAL_SDK_VERSION with TARGET_BUILD_APPS
+ifneq ($(filter-out current system_current test_current core_current,$(LOCAL_SDK_VERSION))$(if $(TARGET_BUILD_USE_PREBUILT_SDKS),$(filter current system_current test_current,$(LOCAL_SDK_VERSION))),)
+# if a numeric LOCAL_SDK_VERSION, or current LOCAL_SDK_VERSION with TARGET_BUILD_USE_PREBUILT_SDKS
 LOCAL_RENDERSCRIPT_INCLUDES := \
     $(HISTORICAL_SDK_VERSIONS_ROOT)/renderscript/clang-include \
     $(HISTORICAL_SDK_VERSIONS_ROOT)/renderscript/include \
@@ -110,7 +110,7 @@
 rs_jni_lib := $(call intermediates-dir-for,SHARED_LIBRARIES,librsjni.so)/librsjni.so
 LOCAL_JNI_SHARED_LIBRARIES += librsjni
 
-ifneq (,$(TARGET_BUILD_APPS)$(FORCE_BUILD_RS_COMPAT))
+ifneq (,$(TARGET_BUILD_USE_PREBUILT_SDKS)$(FORCE_BUILD_RS_COMPAT))
 
 rs_compatibility_jni_libs := $(addprefix \
     $(renderscript_intermediate)/librs., \
diff --git a/core/package_internal.mk b/core/package_internal.mk
index 775ee48..b058891 100644
--- a/core/package_internal.mk
+++ b/core/package_internal.mk
@@ -401,7 +401,7 @@
 # resources.
 ifeq ($(LOCAL_SDK_RES_VERSION),core_current)
 # core_current doesn't contain any framework resources.
-else ifneq ($(filter-out current system_current test_current,$(LOCAL_SDK_RES_VERSION))$(if $(TARGET_BUILD_APPS_USE_PREBUILT_SDK),$(filter current system_current test_current,$(LOCAL_SDK_RES_VERSION))),)
+else ifneq ($(filter-out current system_current test_current,$(LOCAL_SDK_RES_VERSION))$(if $(TARGET_BUILD_USE_PREBUILT_SDKS),$(filter current system_current test_current,$(LOCAL_SDK_RES_VERSION))),)
 # for released sdk versions, the platform resources were built into android.jar.
 framework_res_package_export := \
     $(call resolve-prebuilt-sdk-jar-path,$(LOCAL_SDK_RES_VERSION))
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 01b355e..9c4b509 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -41,7 +41,7 @@
 $(call add_json_bool, Allow_missing_dependencies,        $(ALLOW_MISSING_DEPENDENCIES))
 $(call add_json_bool, Unbundled_build,                   $(TARGET_BUILD_UNBUNDLED))
 $(call add_json_bool, Unbundled_build_apps,              $(TARGET_BUILD_APPS))
-$(call add_json_bool, Unbundled_build_sdks_from_source,  $(UNBUNDLED_BUILD_SDKS_FROM_SOURCE))
+$(call add_json_bool, Always_use_prebuilt_sdks,          $(TARGET_BUILD_USE_PREBUILT_SDKS))
 $(call add_json_bool, Pdk,                               $(filter true,$(TARGET_BUILD_PDK)))
 
 $(call add_json_bool, Debuggable,                        $(filter userdebug eng,$(TARGET_BUILD_VARIANT)))
diff --git a/core/static_java_library.mk b/core/static_java_library.mk
index 81dc2df..7a87322 100644
--- a/core/static_java_library.mk
+++ b/core/static_java_library.mk
@@ -111,7 +111,7 @@
 framework_res_package_export :=
 # Please refer to package.mk
 ifneq ($(LOCAL_NO_STANDARD_LIBRARIES),true)
-ifneq ($(filter-out current system_current test_current,$(LOCAL_SDK_RES_VERSION))$(if $(TARGET_BUILD_APPS_USE_PREBUILT_SDK),$(filter current system_current test_current,$(LOCAL_SDK_RES_VERSION))),)
+ifneq ($(filter-out current system_current test_current,$(LOCAL_SDK_RES_VERSION))$(if $(TARGET_BUILD_USE_PREBUILT_SDKS),$(filter current system_current test_current,$(LOCAL_SDK_RES_VERSION))),)
 framework_res_package_export := \
     $(call resolve-prebuilt-sdk-jar-path,$(LOCAL_SDK_RES_VERSION))
 else
diff --git a/tools/releasetools/Android.bp b/tools/releasetools/Android.bp
index 11f92ab..0ca2b37 100644
--- a/tools/releasetools/Android.bp
+++ b/tools/releasetools/Android.bp
@@ -93,7 +93,9 @@
     srcs: [
         "edify_generator.py",
         "ota_from_target_files.py",
+        "non_ab_ota.py",
         "target_files_diff.py",
+        "ota_utils.py",
     ],
     libs: [
         "releasetools_check_target_files_vintf",
diff --git a/tools/releasetools/check_target_files_vintf.py b/tools/releasetools/check_target_files_vintf.py
index ef66112..0edefac 100755
--- a/tools/releasetools/check_target_files_vintf.py
+++ b/tools/releasetools/check_target_files_vintf.py
@@ -220,6 +220,52 @@
 
   raise ValueError('{} is not a valid directory or zip file'.format(inp))
 
+def CheckVintfIfTrebleEnabled(target_files, target_info):
+  """Checks compatibility info of the input target files.
+
+  Metadata used for compatibility verification is retrieved from target_zip.
+
+  Compatibility should only be checked for devices that have enabled
+  Treble support.
+
+  Args:
+    target_files: Path to zip file containing the source files to be included
+        for OTA. Can also be the path to extracted directory.
+    target_info: The BuildInfo instance that holds the target build info.
+  """
+
+  # Will only proceed if the target has enabled the Treble support (as well as
+  # having a /vendor partition).
+  if not HasTrebleEnabled(target_files, target_info):
+    return
+
+  # Skip adding the compatibility package as a workaround for b/114240221. The
+  # compatibility will always fail on devices without qualified kernels.
+  if OPTIONS.skip_compatibility_check:
+    return
+
+  if not CheckVintf(target_files, target_info):
+    raise RuntimeError("VINTF compatibility check failed")
+
+def HasTrebleEnabled(target_files, target_info):
+  def HasVendorPartition(target_files):
+    if os.path.isdir(target_files):
+      return os.path.isdir(os.path.join(target_files, "VENDOR"))
+    if zipfile.is_zipfile(target_files):
+      return HasPartition(zipfile.ZipFile(target_files), "vendor")
+    raise ValueError("Unknown target_files argument")
+
+  return (HasVendorPartition(target_files) and
+          target_info.GetBuildProp("ro.treble.enabled") == "true")
+
+
+def HasPartition(target_files_zip, partition):
+  try:
+    target_files_zip.getinfo(partition.upper() + "/")
+    return True
+  except KeyError:
+    return False
+
 
 def main(argv):
   args = common.ParseOptions(argv, __doc__)
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 1846a67..89900d3 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1227,7 +1227,7 @@
     cmd = ["mkbootfs", os.path.join(sourcedir, "RAMDISK")]
   p1 = Run(cmd, stdout=subprocess.PIPE)
   if lz4_ramdisks:
-    p2 = Run(["lz4", "-l", "-12" , "--favor-decSpeed"], stdin=p1.stdout,
+    p2 = Run(["lz4", "-l", "-12", "--favor-decSpeed"], stdin=p1.stdout,
              stdout=ramdisk_img.file.fileno())
   else:
     p2 = Run(["minigzip"], stdin=p1.stdout, stdout=ramdisk_img.file.fileno())
diff --git a/tools/releasetools/non_ab_ota.py b/tools/releasetools/non_ab_ota.py
new file mode 100644
index 0000000..3a87957
--- /dev/null
+++ b/tools/releasetools/non_ab_ota.py
@@ -0,0 +1,684 @@
+# Copyright (C) 2020 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.
+
+import collections
+import logging
+import os
+import zipfile
+
+import common
+import edify_generator
+import verity_utils
+from check_target_files_vintf import CheckVintfIfTrebleEnabled, HasPartition
+from common import OPTIONS
+from ota_utils import UNZIP_PATTERN, FinalizeMetadata, GetPackageMetadata, PropertyFiles
+
+logger = logging.getLogger(__name__)
+
+
+def GetBlockDifferences(target_zip, source_zip, target_info, source_info,
+                        device_specific):
+  """Returns a ordered dict of block differences with partition name as key."""
+
+  def GetIncrementalBlockDifferenceForPartition(name):
+    if not HasPartition(source_zip, name):
+      raise RuntimeError(
+          "can't generate incremental that adds {}".format(name))
+
+    partition_src = common.GetUserImage(name, OPTIONS.source_tmp, source_zip,
+                                        info_dict=source_info,
+                                        allow_shared_blocks=allow_shared_blocks)
+
+    hashtree_info_generator = verity_utils.CreateHashtreeInfoGenerator(
+        name, 4096, target_info)
+    partition_tgt = common.GetUserImage(name, OPTIONS.target_tmp, target_zip,
+                                        info_dict=target_info,
+                                        allow_shared_blocks=allow_shared_blocks,
+                                        hashtree_info_generator=hashtree_info_generator)
+
+    # Check the first block of the source system partition for remount R/W only
+    # if the filesystem is ext4.
+    partition_source_info = source_info["fstab"]["/" + name]
+    check_first_block = partition_source_info.fs_type == "ext4"
+    # Disable using imgdiff for squashfs. 'imgdiff -z' expects input files to be
+    # in zip formats. However with squashfs, a) all files are compressed in LZ4;
+    # b) the blocks listed in block map may not contain all the bytes for a
+    # given file (because they're rounded to be 4K-aligned).
+    partition_target_info = target_info["fstab"]["/" + name]
+    disable_imgdiff = (partition_source_info.fs_type == "squashfs" or
+                       partition_target_info.fs_type == "squashfs")
+    return common.BlockDifference(name, partition_tgt, partition_src,
+                                  check_first_block,
+                                  version=blockimgdiff_version,
+                                  disable_imgdiff=disable_imgdiff)
+
+  if source_zip:
+    # See notes in common.GetUserImage()
+    allow_shared_blocks = (source_info.get('ext4_share_dup_blocks') == "true" or
+                           target_info.get('ext4_share_dup_blocks') == "true")
+    blockimgdiff_version = max(
+        int(i) for i in target_info.get(
+            "blockimgdiff_versions", "1").split(","))
+    assert blockimgdiff_version >= 3
+
+  block_diff_dict = collections.OrderedDict()
+  partition_names = ["system", "vendor", "product", "odm", "system_ext",
+                     "vendor_dlkm", "odm_dlkm"]
+  for partition in partition_names:
+    if not HasPartition(target_zip, partition):
+      continue
+    # Full OTA update.
+    if not source_zip:
+      tgt = common.GetUserImage(partition, OPTIONS.input_tmp, target_zip,
+                                info_dict=target_info,
+                                reset_file_map=True)
+      block_diff_dict[partition] = common.BlockDifference(partition, tgt,
+                                                          src=None)
+    # Incremental OTA update.
+    else:
+      block_diff_dict[partition] = GetIncrementalBlockDifferenceForPartition(
+          partition)
+  assert "system" in block_diff_dict
+
+  # Get the block diffs from the device specific script. If there is a
+  # duplicate block diff for a partition, ignore the diff in the generic script
+  # and use the one in the device specific script instead.
+  if source_zip:
+    device_specific_diffs = device_specific.IncrementalOTA_GetBlockDifferences()
+    function_name = "IncrementalOTA_GetBlockDifferences"
+  else:
+    device_specific_diffs = device_specific.FullOTA_GetBlockDifferences()
+    function_name = "FullOTA_GetBlockDifferences"
+
+  if device_specific_diffs:
+    assert all(isinstance(diff, common.BlockDifference)
+               for diff in device_specific_diffs), \
+        "{} is not returning a list of BlockDifference objects".format(
+            function_name)
+    for diff in device_specific_diffs:
+      if diff.partition in block_diff_dict:
+        logger.warning("Duplicate block difference found. Device specific block"
+                       " diff for partition '%s' overrides the one in generic"
+                       " script.", diff.partition)
+      block_diff_dict[diff.partition] = diff
+
+  return block_diff_dict
+
+
+def WriteFullOTAPackage(input_zip, output_file):
+  target_info = common.BuildInfo(OPTIONS.info_dict, OPTIONS.oem_dicts)
+
+  # We don't know what version it will be installed on top of. We expect the API
+  # just won't change very often. Similarly for fstab, it might have changed in
+  # the target build.
+  target_api_version = target_info["recovery_api_version"]
+  script = edify_generator.EdifyGenerator(target_api_version, target_info)
+
+  if target_info.oem_props and not OPTIONS.oem_no_mount:
+    target_info.WriteMountOemScript(script)
+
+  metadata = GetPackageMetadata(target_info)
+
+  if not OPTIONS.no_signing:
+    staging_file = common.MakeTempFile(suffix='.zip')
+  else:
+    staging_file = output_file
+
+  output_zip = zipfile.ZipFile(
+      staging_file, "w", compression=zipfile.ZIP_DEFLATED)
+
+  device_specific = common.DeviceSpecificParams(
+      input_zip=input_zip,
+      input_version=target_api_version,
+      output_zip=output_zip,
+      script=script,
+      input_tmp=OPTIONS.input_tmp,
+      metadata=metadata,
+      info_dict=OPTIONS.info_dict)
+
+  assert HasRecoveryPatch(input_zip, info_dict=OPTIONS.info_dict)
+
+  # Assertions (e.g. downgrade check, device properties check).
+  ts = target_info.GetBuildProp("ro.build.date.utc")
+  ts_text = target_info.GetBuildProp("ro.build.date")
+  script.AssertOlderBuild(ts, ts_text)
+
+  target_info.WriteDeviceAssertions(script, OPTIONS.oem_no_mount)
+  device_specific.FullOTA_Assertions()
+
+  block_diff_dict = GetBlockDifferences(target_zip=input_zip, source_zip=None,
+                                        target_info=target_info,
+                                        source_info=None,
+                                        device_specific=device_specific)
+
+  # Two-step package strategy (in chronological order, which is *not*
+  # the order in which the generated script has things):
+  #
+  # if stage is not "2/3" or "3/3":
+  #    write recovery image to boot partition
+  #    set stage to "2/3"
+  #    reboot to boot partition and restart recovery
+  # else if stage is "2/3":
+  #    write recovery image to recovery partition
+  #    set stage to "3/3"
+  #    reboot to recovery partition and restart recovery
+  # else:
+  #    (stage must be "3/3")
+  #    set stage to ""
+  #    do normal full package installation:
+  #       wipe and install system, boot image, etc.
+  #       set up system to update recovery partition on first boot
+  #    complete script normally
+  #    (allow recovery to mark itself finished and reboot)
+
+  recovery_img = common.GetBootableImage("recovery.img", "recovery.img",
+                                         OPTIONS.input_tmp, "RECOVERY")
+  if OPTIONS.two_step:
+    if not target_info.get("multistage_support"):
+      assert False, "two-step packages not supported by this build"
+    fs = target_info["fstab"]["/misc"]
+    assert fs.fs_type.upper() == "EMMC", \
+        "two-step packages only supported on devices with EMMC /misc partitions"
+    bcb_dev = {"bcb_dev": fs.device}
+    common.ZipWriteStr(output_zip, "recovery.img", recovery_img.data)
+    script.AppendExtra("""
+if get_stage("%(bcb_dev)s") == "2/3" then
+""" % bcb_dev)
+
+    # Stage 2/3: Write recovery image to /recovery (currently running /boot).
+    script.Comment("Stage 2/3")
+    script.WriteRawImage("/recovery", "recovery.img")
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "3/3");
+reboot_now("%(bcb_dev)s", "recovery");
+else if get_stage("%(bcb_dev)s") == "3/3" then
+""" % bcb_dev)
+
+    # Stage 3/3: Make changes.
+    script.Comment("Stage 3/3")
+
+  # Dump fingerprints
+  script.Print("Target: {}".format(target_info.fingerprint))
+
+  device_specific.FullOTA_InstallBegin()
+
+  # All other partitions as well as the data wipe use 10% of the progress, and
+  # the update of the system partition takes the remaining progress.
+  system_progress = 0.9 - (len(block_diff_dict) - 1) * 0.1
+  if OPTIONS.wipe_user_data:
+    system_progress -= 0.1
+  progress_dict = {partition: 0.1 for partition in block_diff_dict}
+  progress_dict["system"] = system_progress
+
+  if target_info.get('use_dynamic_partitions') == "true":
+    # Use empty source_info_dict to indicate that all partitions / groups must
+    # be re-added.
+    dynamic_partitions_diff = common.DynamicPartitionsDifference(
+        info_dict=OPTIONS.info_dict,
+        block_diffs=block_diff_dict.values(),
+        progress_dict=progress_dict)
+    dynamic_partitions_diff.WriteScript(script, output_zip,
+                                        write_verify_script=OPTIONS.verify)
+  else:
+    for block_diff in block_diff_dict.values():
+      block_diff.WriteScript(script, output_zip,
+                             progress=progress_dict.get(block_diff.partition),
+                             write_verify_script=OPTIONS.verify)
+
+  CheckVintfIfTrebleEnabled(OPTIONS.input_tmp, target_info)
+
+  boot_img = common.GetBootableImage(
+      "boot.img", "boot.img", OPTIONS.input_tmp, "BOOT")
+  common.CheckSize(boot_img.data, "boot.img", target_info)
+  common.ZipWriteStr(output_zip, "boot.img", boot_img.data)
+
+  script.WriteRawImage("/boot", "boot.img")
+
+  script.ShowProgress(0.1, 10)
+  device_specific.FullOTA_InstallEnd()
+
+  if OPTIONS.extra_script is not None:
+    script.AppendExtra(OPTIONS.extra_script)
+
+  script.UnmountAll()
+
+  if OPTIONS.wipe_user_data:
+    script.ShowProgress(0.1, 10)
+    script.FormatPartition("/data")
+
+  if OPTIONS.two_step:
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "");
+""" % bcb_dev)
+    script.AppendExtra("else\n")
+
+    # Stage 1/3: Nothing to verify for full OTA. Write recovery image to /boot.
+    script.Comment("Stage 1/3")
+    _WriteRecoveryImageToBoot(script, output_zip)
+
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "2/3");
+reboot_now("%(bcb_dev)s", "");
+endif;
+endif;
+""" % bcb_dev)
+
+  script.SetProgress(1)
+  script.AddToZip(input_zip, output_zip, input_path=OPTIONS.updater_binary)
+  metadata["ota-required-cache"] = str(script.required_cache)
+
+  # We haven't written the metadata entry, which will be done in
+  # FinalizeMetadata.
+  common.ZipClose(output_zip)
+
+  needed_property_files = (
+      NonAbOtaPropertyFiles(),
+  )
+  FinalizeMetadata(metadata, staging_file, output_file, needed_property_files)
+
+
+def WriteBlockIncrementalOTAPackage(target_zip, source_zip, output_file):
+  target_info = common.BuildInfo(OPTIONS.target_info_dict, OPTIONS.oem_dicts)
+  source_info = common.BuildInfo(OPTIONS.source_info_dict, OPTIONS.oem_dicts)
+
+  target_api_version = target_info["recovery_api_version"]
+  source_api_version = source_info["recovery_api_version"]
+  if source_api_version == 0:
+    logger.warning(
+        "Generating edify script for a source that can't install it.")
+
+  script = edify_generator.EdifyGenerator(
+      source_api_version, target_info, fstab=source_info["fstab"])
+
+  if target_info.oem_props or source_info.oem_props:
+    if not OPTIONS.oem_no_mount:
+      source_info.WriteMountOemScript(script)
+
+  metadata = GetPackageMetadata(target_info, source_info)
+
+  if not OPTIONS.no_signing:
+    staging_file = common.MakeTempFile(suffix='.zip')
+  else:
+    staging_file = output_file
+
+  output_zip = zipfile.ZipFile(
+      staging_file, "w", compression=zipfile.ZIP_DEFLATED)
+
+  device_specific = common.DeviceSpecificParams(
+      source_zip=source_zip,
+      source_version=source_api_version,
+      source_tmp=OPTIONS.source_tmp,
+      target_zip=target_zip,
+      target_version=target_api_version,
+      target_tmp=OPTIONS.target_tmp,
+      output_zip=output_zip,
+      script=script,
+      metadata=metadata,
+      info_dict=source_info)
+
+  source_boot = common.GetBootableImage(
+      "/tmp/boot.img", "boot.img", OPTIONS.source_tmp, "BOOT", source_info)
+  target_boot = common.GetBootableImage(
+      "/tmp/boot.img", "boot.img", OPTIONS.target_tmp, "BOOT", target_info)
+  updating_boot = (not OPTIONS.two_step and
+                   (source_boot.data != target_boot.data))
+
+  target_recovery = common.GetBootableImage(
+      "/tmp/recovery.img", "recovery.img", OPTIONS.target_tmp, "RECOVERY")
+
+  block_diff_dict = GetBlockDifferences(target_zip=target_zip,
+                                        source_zip=source_zip,
+                                        target_info=target_info,
+                                        source_info=source_info,
+                                        device_specific=device_specific)
+
+  CheckVintfIfTrebleEnabled(OPTIONS.target_tmp, target_info)
+
+  # Assertions (e.g. device properties check).
+  target_info.WriteDeviceAssertions(script, OPTIONS.oem_no_mount)
+  device_specific.IncrementalOTA_Assertions()
+
+  # Two-step incremental package strategy (in chronological order,
+  # which is *not* the order in which the generated script has
+  # things):
+  #
+  # if stage is not "2/3" or "3/3":
+  #    do verification on current system
+  #    write recovery image to boot partition
+  #    set stage to "2/3"
+  #    reboot to boot partition and restart recovery
+  # else if stage is "2/3":
+  #    write recovery image to recovery partition
+  #    set stage to "3/3"
+  #    reboot to recovery partition and restart recovery
+  # else:
+  #    (stage must be "3/3")
+  #    perform update:
+  #       patch system files, etc.
+  #       force full install of new boot image
+  #       set up system to update recovery partition on first boot
+  #    complete script normally
+  #    (allow recovery to mark itself finished and reboot)
+
+  if OPTIONS.two_step:
+    if not source_info.get("multistage_support"):
+      assert False, "two-step packages not supported by this build"
+    fs = source_info["fstab"]["/misc"]
+    assert fs.fs_type.upper() == "EMMC", \
+        "two-step packages only supported on devices with EMMC /misc partitions"
+    bcb_dev = {"bcb_dev": fs.device}
+    common.ZipWriteStr(output_zip, "recovery.img", target_recovery.data)
+    script.AppendExtra("""
+if get_stage("%(bcb_dev)s") == "2/3" then
+""" % bcb_dev)
+
+    # Stage 2/3: Write recovery image to /recovery (currently running /boot).
+    script.Comment("Stage 2/3")
+    script.AppendExtra("sleep(20);\n")
+    script.WriteRawImage("/recovery", "recovery.img")
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "3/3");
+reboot_now("%(bcb_dev)s", "recovery");
+else if get_stage("%(bcb_dev)s") != "3/3" then
+""" % bcb_dev)
+
+    # Stage 1/3: (a) Verify the current system.
+    script.Comment("Stage 1/3")
+
+  # Dump fingerprints
+  script.Print("Source: {}".format(source_info.fingerprint))
+  script.Print("Target: {}".format(target_info.fingerprint))
+
+  script.Print("Verifying current system...")
+
+  device_specific.IncrementalOTA_VerifyBegin()
+
+  WriteFingerprintAssertion(script, target_info, source_info)
+
+  # Check the required cache size (i.e. stashed blocks).
+  required_cache_sizes = [diff.required_cache for diff in
+                          block_diff_dict.values()]
+  if updating_boot:
+    boot_type, boot_device_expr = common.GetTypeAndDeviceExpr("/boot",
+                                                              source_info)
+    d = common.Difference(target_boot, source_boot)
+    _, _, d = d.ComputePatch()
+    if d is None:
+      include_full_boot = True
+      common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
+    else:
+      include_full_boot = False
+
+      logger.info(
+          "boot      target: %d  source: %d  diff: %d", target_boot.size,
+          source_boot.size, len(d))
+
+      common.ZipWriteStr(output_zip, "boot.img.p", d)
+
+      target_expr = 'concat("{}:",{},":{}:{}")'.format(
+          boot_type, boot_device_expr, target_boot.size, target_boot.sha1)
+      source_expr = 'concat("{}:",{},":{}:{}")'.format(
+          boot_type, boot_device_expr, source_boot.size, source_boot.sha1)
+      script.PatchPartitionExprCheck(target_expr, source_expr)
+
+      required_cache_sizes.append(target_boot.size)
+
+  if required_cache_sizes:
+    script.CacheFreeSpaceCheck(max(required_cache_sizes))
+
+  # Verify the existing partitions.
+  for diff in block_diff_dict.values():
+    diff.WriteVerifyScript(script, touched_blocks_only=True)
+
+  device_specific.IncrementalOTA_VerifyEnd()
+
+  if OPTIONS.two_step:
+    # Stage 1/3: (b) Write recovery image to /boot.
+    _WriteRecoveryImageToBoot(script, output_zip)
+
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "2/3");
+reboot_now("%(bcb_dev)s", "");
+else
+""" % bcb_dev)
+
+    # Stage 3/3: Make changes.
+    script.Comment("Stage 3/3")
+
+  script.Comment("---- start making changes here ----")
+
+  device_specific.IncrementalOTA_InstallBegin()
+
+  progress_dict = {partition: 0.1 for partition in block_diff_dict}
+  progress_dict["system"] = 1 - len(block_diff_dict) * 0.1
+
+  if OPTIONS.source_info_dict.get("use_dynamic_partitions") == "true":
+    if OPTIONS.target_info_dict.get("use_dynamic_partitions") != "true":
+      raise RuntimeError(
+          "can't generate incremental that disables dynamic partitions")
+    dynamic_partitions_diff = common.DynamicPartitionsDifference(
+        info_dict=OPTIONS.target_info_dict,
+        source_info_dict=OPTIONS.source_info_dict,
+        block_diffs=block_diff_dict.values(),
+        progress_dict=progress_dict)
+    dynamic_partitions_diff.WriteScript(
+        script, output_zip, write_verify_script=OPTIONS.verify)
+  else:
+    for block_diff in block_diff_dict.values():
+      block_diff.WriteScript(script, output_zip,
+                             progress=progress_dict.get(block_diff.partition),
+                             write_verify_script=OPTIONS.verify)
+
+  if OPTIONS.two_step:
+    common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
+    script.WriteRawImage("/boot", "boot.img")
+    logger.info("writing full boot image (forced by two-step mode)")
+
+  if not OPTIONS.two_step:
+    if updating_boot:
+      if include_full_boot:
+        logger.info("boot image changed; including full.")
+        script.Print("Installing boot image...")
+        script.WriteRawImage("/boot", "boot.img")
+      else:
+        # Produce the boot image by applying a patch to the current
+        # contents of the boot partition, and write it back to the
+        # partition.
+        logger.info("boot image changed; including patch.")
+        script.Print("Patching boot image...")
+        script.ShowProgress(0.1, 10)
+        target_expr = 'concat("{}:",{},":{}:{}")'.format(
+            boot_type, boot_device_expr, target_boot.size, target_boot.sha1)
+        source_expr = 'concat("{}:",{},":{}:{}")'.format(
+            boot_type, boot_device_expr, source_boot.size, source_boot.sha1)
+        script.PatchPartitionExpr(target_expr, source_expr, '"boot.img.p"')
+    else:
+      logger.info("boot image unchanged; skipping.")
+
+  # Do device-specific installation (eg, write radio image).
+  device_specific.IncrementalOTA_InstallEnd()
+
+  if OPTIONS.extra_script is not None:
+    script.AppendExtra(OPTIONS.extra_script)
+
+  if OPTIONS.wipe_user_data:
+    script.Print("Erasing user data...")
+    script.FormatPartition("/data")
+
+  if OPTIONS.two_step:
+    script.AppendExtra("""
+set_stage("%(bcb_dev)s", "");
+endif;
+endif;
+""" % bcb_dev)
+
+  script.SetProgress(1)
+  # For downgrade OTAs, we prefer to use the update-binary in the source
+  # build that is actually newer than the one in the target build.
+  if OPTIONS.downgrade:
+    script.AddToZip(source_zip, output_zip, input_path=OPTIONS.updater_binary)
+  else:
+    script.AddToZip(target_zip, output_zip, input_path=OPTIONS.updater_binary)
+  metadata["ota-required-cache"] = str(script.required_cache)
+
+  # We haven't written the metadata entry yet, which will be handled in
+  # FinalizeMetadata().
+  common.ZipClose(output_zip)
+
+  # Sign the generated zip package unless no_signing is specified.
+  needed_property_files = (
+      NonAbOtaPropertyFiles(),
+  )
+  FinalizeMetadata(metadata, staging_file, output_file, needed_property_files)
+
+
+def GenerateNonAbOtaPackage(target_file, output_file, source_file=None):
+  """Generates a non-A/B OTA package."""
+  # Check the loaded info dicts first.
+  if OPTIONS.info_dict.get("no_recovery") == "true":
+    raise common.ExternalError(
+        "--- target build has specified no recovery ---")
+
+  # Non-A/B OTAs rely on /cache partition to store temporary files.
+  cache_size = OPTIONS.info_dict.get("cache_size")
+  if cache_size is None:
+    logger.warning("--- can't determine the cache partition size ---")
+  OPTIONS.cache_size = cache_size
+
+  if OPTIONS.extra_script is not None:
+    with open(OPTIONS.extra_script) as fp:
+      OPTIONS.extra_script = fp.read()
+
+  if OPTIONS.extracted_input is not None:
+    OPTIONS.input_tmp = OPTIONS.extracted_input
+  else:
+    logger.info("unzipping target target-files...")
+    OPTIONS.input_tmp = common.UnzipTemp(target_file, UNZIP_PATTERN)
+  OPTIONS.target_tmp = OPTIONS.input_tmp
+
+  # If the caller explicitly specified the device-specific extensions path via
+  # -s / --device_specific, use that. Otherwise, use META/releasetools.py if it
+  # is present in the target target_files. Otherwise, take the path of the file
+  # from 'tool_extensions' in the info dict and look for that in the local
+  # filesystem, relative to the current directory.
+  if OPTIONS.device_specific is None:
+    from_input = os.path.join(OPTIONS.input_tmp, "META", "releasetools.py")
+    if os.path.exists(from_input):
+      logger.info("(using device-specific extensions from target_files)")
+      OPTIONS.device_specific = from_input
+    else:
+      OPTIONS.device_specific = OPTIONS.info_dict.get("tool_extensions")
+
+  if OPTIONS.device_specific is not None:
+    OPTIONS.device_specific = os.path.abspath(OPTIONS.device_specific)
+
+  # Generate a full OTA.
+  if source_file is None:
+    with zipfile.ZipFile(target_file) as input_zip:
+      WriteFullOTAPackage(
+          input_zip,
+          output_file)
+
+  # Generate an incremental OTA.
+  else:
+    logger.info("unzipping source target-files...")
+    OPTIONS.source_tmp = common.UnzipTemp(
+        OPTIONS.incremental_source, UNZIP_PATTERN)
+    with zipfile.ZipFile(target_file) as input_zip, \
+            zipfile.ZipFile(source_file) as source_zip:
+      WriteBlockIncrementalOTAPackage(
+          input_zip,
+          source_zip,
+          output_file)
+
+
+def WriteFingerprintAssertion(script, target_info, source_info):
+  source_oem_props = source_info.oem_props
+  target_oem_props = target_info.oem_props
+
+  if source_oem_props is None and target_oem_props is None:
+    script.AssertSomeFingerprint(
+        source_info.fingerprint, target_info.fingerprint)
+  elif source_oem_props is not None and target_oem_props is not None:
+    script.AssertSomeThumbprint(
+        target_info.GetBuildProp("ro.build.thumbprint"),
+        source_info.GetBuildProp("ro.build.thumbprint"))
+  elif source_oem_props is None and target_oem_props is not None:
+    script.AssertFingerprintOrThumbprint(
+        source_info.fingerprint,
+        target_info.GetBuildProp("ro.build.thumbprint"))
+  else:
+    script.AssertFingerprintOrThumbprint(
+        target_info.fingerprint,
+        source_info.GetBuildProp("ro.build.thumbprint"))
+
+
+class NonAbOtaPropertyFiles(PropertyFiles):
+  """The property-files for non-A/B OTA.
+
+  For non-A/B OTA, the property-files string contains the info for METADATA
+  entry, with which a system updater can be fetched the package metadata prior
+  to downloading the entire package.
+  """
+
+  def __init__(self):
+    super(NonAbOtaPropertyFiles, self).__init__()
+    self.name = 'ota-property-files'
+
+
+def _WriteRecoveryImageToBoot(script, output_zip):
+  """Find and write recovery image to /boot in two-step OTA.
+
+  In two-step OTAs, we write recovery image to /boot as the first step so that
+  we can reboot to there and install a new recovery image to /recovery.
+  A special "recovery-two-step.img" will be preferred, which encodes the correct
+  path of "/boot". Otherwise the device may show "device is corrupt" message
+  when booting into /boot.
+
+  Fall back to using the regular recovery.img if the two-step recovery image
+  doesn't exist. Note that rebuilding the special image at this point may be
+  infeasible, because we don't have the desired boot signer and keys when
+  calling ota_from_target_files.py.
+  """
+
+  recovery_two_step_img_name = "recovery-two-step.img"
+  recovery_two_step_img_path = os.path.join(
+      OPTIONS.input_tmp, "OTA", recovery_two_step_img_name)
+  if os.path.exists(recovery_two_step_img_path):
+    common.ZipWrite(
+        output_zip,
+        recovery_two_step_img_path,
+        arcname=recovery_two_step_img_name)
+    logger.info(
+        "two-step package: using %s in stage 1/3", recovery_two_step_img_name)
+    script.WriteRawImage("/boot", recovery_two_step_img_name)
+  else:
+    logger.info("two-step package: using recovery.img in stage 1/3")
+    # The "recovery.img" entry has been written into package earlier.
+    script.WriteRawImage("/boot", "recovery.img")
+
+
+def HasRecoveryPatch(target_files_zip, info_dict):
+  board_uses_vendorimage = info_dict.get("board_uses_vendorimage") == "true"
+
+  if board_uses_vendorimage:
+    target_files_dir = "VENDOR"
+  else:
+    target_files_dir = "SYSTEM/vendor"
+
+  patch = "%s/recovery-from-boot.p" % target_files_dir
+  img = "%s/etc/recovery.img" % target_files_dir
+
+  namelist = target_files_zip.namelist()
+  return patch in namelist or img in namelist
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index b70044e..f42974f 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -206,9 +206,6 @@
 
 from __future__ import print_function
 
-import collections
-import copy
-import itertools
 import logging
 import multiprocessing
 import os.path
@@ -218,12 +215,12 @@
 import sys
 import zipfile
 
-import check_target_files_vintf
 import common
-import edify_generator
 import target_files_diff
-import verity_utils
-
+from check_target_files_vintf import CheckVintfIfTrebleEnabled
+from non_ab_ota import GenerateNonAbOtaPackage
+from ota_utils import (UNZIP_PATTERN, FinalizeMetadata, GetPackageMetadata,
+                       PropertyFiles)
 
 if sys.hexversion < 0x02070000:
   print("Python 2.7 or newer is required.", file=sys.stderr)
@@ -270,11 +267,10 @@
 OPTIONS.boot_variable_file = None
 
 
-METADATA_NAME = 'META-INF/com/android/metadata'
 POSTINSTALL_CONFIG = 'META/postinstall_config.txt'
 DYNAMIC_PARTITION_INFO = 'META/dynamic_partitions_info.txt'
 AB_PARTITIONS = 'META/ab_partitions.txt'
-UNZIP_PATTERN = ['IMAGES/*', 'META/*', 'OTA/*', 'RADIO/*']
+
 # Files to be unzipped for target diffing purpose.
 TARGET_DIFFING_UNZIP_PATTERN = ['BOOT', 'RECOVERY', 'SYSTEM/*', 'VENDOR/*',
                                 'PRODUCT/*', 'SYSTEM_EXT/*', 'ODM/*',
@@ -488,13 +484,6 @@
                     compress_type=zipfile.ZIP_STORED)
 
 
-def SignOutput(temp_zip_name, output_zip_name):
-  pw = OPTIONS.key_passwords[OPTIONS.package_key]
-
-  common.SignFile(temp_zip_name, output_zip_name, OPTIONS.package_key, pw,
-                  whole_file=True)
-
-
 def _LoadOemDicts(oem_source):
   """Returns the list of loaded OEM properties dict."""
   if not oem_source:
@@ -507,658 +496,6 @@
   return oem_dicts
 
 
-def _WriteRecoveryImageToBoot(script, output_zip):
-  """Find and write recovery image to /boot in two-step OTA.
-
-  In two-step OTAs, we write recovery image to /boot as the first step so that
-  we can reboot to there and install a new recovery image to /recovery.
-  A special "recovery-two-step.img" will be preferred, which encodes the correct
-  path of "/boot". Otherwise the device may show "device is corrupt" message
-  when booting into /boot.
-
-  Fall back to using the regular recovery.img if the two-step recovery image
-  doesn't exist. Note that rebuilding the special image at this point may be
-  infeasible, because we don't have the desired boot signer and keys when
-  calling ota_from_target_files.py.
-  """
-
-  recovery_two_step_img_name = "recovery-two-step.img"
-  recovery_two_step_img_path = os.path.join(
-      OPTIONS.input_tmp, "OTA", recovery_two_step_img_name)
-  if os.path.exists(recovery_two_step_img_path):
-    common.ZipWrite(
-        output_zip,
-        recovery_two_step_img_path,
-        arcname=recovery_two_step_img_name)
-    logger.info(
-        "two-step package: using %s in stage 1/3", recovery_two_step_img_name)
-    script.WriteRawImage("/boot", recovery_two_step_img_name)
-  else:
-    logger.info("two-step package: using recovery.img in stage 1/3")
-    # The "recovery.img" entry has been written into package earlier.
-    script.WriteRawImage("/boot", "recovery.img")
-
-
-def HasRecoveryPatch(target_files_zip, info_dict):
-  board_uses_vendorimage = info_dict.get("board_uses_vendorimage") == "true"
-
-  if board_uses_vendorimage:
-    target_files_dir = "VENDOR"
-  else:
-    target_files_dir = "SYSTEM/vendor"
-
-  patch = "%s/recovery-from-boot.p" % target_files_dir
-  img = "%s/etc/recovery.img" % target_files_dir
-
-  namelist = target_files_zip.namelist()
-  return patch in namelist or img in namelist
-
-
-def HasPartition(target_files_zip, partition):
-  try:
-    target_files_zip.getinfo(partition.upper() + "/")
-    return True
-  except KeyError:
-    return False
-
-
-def HasTrebleEnabled(target_files, target_info):
-  def HasVendorPartition(target_files):
-    if os.path.isdir(target_files):
-      return os.path.isdir(os.path.join(target_files, "VENDOR"))
-    if zipfile.is_zipfile(target_files):
-      return HasPartition(zipfile.ZipFile(target_files), "vendor")
-    raise ValueError("Unknown target_files argument")
-
-  return (HasVendorPartition(target_files) and
-          target_info.GetBuildProp("ro.treble.enabled") == "true")
-
-
-def WriteFingerprintAssertion(script, target_info, source_info):
-  source_oem_props = source_info.oem_props
-  target_oem_props = target_info.oem_props
-
-  if source_oem_props is None and target_oem_props is None:
-    script.AssertSomeFingerprint(
-        source_info.fingerprint, target_info.fingerprint)
-  elif source_oem_props is not None and target_oem_props is not None:
-    script.AssertSomeThumbprint(
-        target_info.GetBuildProp("ro.build.thumbprint"),
-        source_info.GetBuildProp("ro.build.thumbprint"))
-  elif source_oem_props is None and target_oem_props is not None:
-    script.AssertFingerprintOrThumbprint(
-        source_info.fingerprint,
-        target_info.GetBuildProp("ro.build.thumbprint"))
-  else:
-    script.AssertFingerprintOrThumbprint(
-        target_info.fingerprint,
-        source_info.GetBuildProp("ro.build.thumbprint"))
-
-
-def CheckVintfIfTrebleEnabled(target_files, target_info):
-  """Checks compatibility info of the input target files.
-
-  Metadata used for compatibility verification is retrieved from target_zip.
-
-  Compatibility should only be checked for devices that have enabled
-  Treble support.
-
-  Args:
-    target_files: Path to zip file containing the source files to be included
-        for OTA. Can also be the path to extracted directory.
-    target_info: The BuildInfo instance that holds the target build info.
-  """
-
-  # Will only proceed if the target has enabled the Treble support (as well as
-  # having a /vendor partition).
-  if not HasTrebleEnabled(target_files, target_info):
-    return
-
-  # Skip adding the compatibility package as a workaround for b/114240221. The
-  # compatibility will always fail on devices without qualified kernels.
-  if OPTIONS.skip_compatibility_check:
-    return
-
-  if not check_target_files_vintf.CheckVintf(target_files, target_info):
-    raise RuntimeError("VINTF compatibility check failed")
-
-
-def GetBlockDifferences(target_zip, source_zip, target_info, source_info,
-                        device_specific):
-  """Returns a ordered dict of block differences with partition name as key."""
-
-  def GetIncrementalBlockDifferenceForPartition(name):
-    if not HasPartition(source_zip, name):
-      raise RuntimeError(
-          "can't generate incremental that adds {}".format(name))
-
-    partition_src = common.GetUserImage(name, OPTIONS.source_tmp, source_zip,
-                                        info_dict=source_info,
-                                        allow_shared_blocks=allow_shared_blocks)
-
-    hashtree_info_generator = verity_utils.CreateHashtreeInfoGenerator(
-        name, 4096, target_info)
-    partition_tgt = common.GetUserImage(name, OPTIONS.target_tmp, target_zip,
-                                        info_dict=target_info,
-                                        allow_shared_blocks=allow_shared_blocks,
-                                        hashtree_info_generator=hashtree_info_generator)
-
-    # Check the first block of the source system partition for remount R/W only
-    # if the filesystem is ext4.
-    partition_source_info = source_info["fstab"]["/" + name]
-    check_first_block = partition_source_info.fs_type == "ext4"
-    # Disable using imgdiff for squashfs. 'imgdiff -z' expects input files to be
-    # in zip formats. However with squashfs, a) all files are compressed in LZ4;
-    # b) the blocks listed in block map may not contain all the bytes for a
-    # given file (because they're rounded to be 4K-aligned).
-    partition_target_info = target_info["fstab"]["/" + name]
-    disable_imgdiff = (partition_source_info.fs_type == "squashfs" or
-                       partition_target_info.fs_type == "squashfs")
-    return common.BlockDifference(name, partition_tgt, partition_src,
-                                  check_first_block,
-                                  version=blockimgdiff_version,
-                                  disable_imgdiff=disable_imgdiff)
-
-  if source_zip:
-    # See notes in common.GetUserImage()
-    allow_shared_blocks = (source_info.get('ext4_share_dup_blocks') == "true" or
-                           target_info.get('ext4_share_dup_blocks') == "true")
-    blockimgdiff_version = max(
-        int(i) for i in target_info.get(
-            "blockimgdiff_versions", "1").split(","))
-    assert blockimgdiff_version >= 3
-
-  block_diff_dict = collections.OrderedDict()
-  partition_names = ["system", "vendor", "product", "odm", "system_ext",
-                     "vendor_dlkm", "odm_dlkm"]
-  for partition in partition_names:
-    if not HasPartition(target_zip, partition):
-      continue
-    # Full OTA update.
-    if not source_zip:
-      tgt = common.GetUserImage(partition, OPTIONS.input_tmp, target_zip,
-                                info_dict=target_info,
-                                reset_file_map=True)
-      block_diff_dict[partition] = common.BlockDifference(partition, tgt,
-                                                          src=None)
-    # Incremental OTA update.
-    else:
-      block_diff_dict[partition] = GetIncrementalBlockDifferenceForPartition(
-          partition)
-  assert "system" in block_diff_dict
-
-  # Get the block diffs from the device specific script. If there is a
-  # duplicate block diff for a partition, ignore the diff in the generic script
-  # and use the one in the device specific script instead.
-  if source_zip:
-    device_specific_diffs = device_specific.IncrementalOTA_GetBlockDifferences()
-    function_name = "IncrementalOTA_GetBlockDifferences"
-  else:
-    device_specific_diffs = device_specific.FullOTA_GetBlockDifferences()
-    function_name = "FullOTA_GetBlockDifferences"
-
-  if device_specific_diffs:
-    assert all(isinstance(diff, common.BlockDifference)
-               for diff in device_specific_diffs), \
-        "{} is not returning a list of BlockDifference objects".format(
-            function_name)
-    for diff in device_specific_diffs:
-      if diff.partition in block_diff_dict:
-        logger.warning("Duplicate block difference found. Device specific block"
-                       " diff for partition '%s' overrides the one in generic"
-                       " script.", diff.partition)
-      block_diff_dict[diff.partition] = diff
-
-  return block_diff_dict
-
-
-def WriteFullOTAPackage(input_zip, output_file):
-  target_info = common.BuildInfo(OPTIONS.info_dict, OPTIONS.oem_dicts)
-
-  # We don't know what version it will be installed on top of. We expect the API
-  # just won't change very often. Similarly for fstab, it might have changed in
-  # the target build.
-  target_api_version = target_info["recovery_api_version"]
-  script = edify_generator.EdifyGenerator(target_api_version, target_info)
-
-  if target_info.oem_props and not OPTIONS.oem_no_mount:
-    target_info.WriteMountOemScript(script)
-
-  metadata = GetPackageMetadata(target_info)
-
-  if not OPTIONS.no_signing:
-    staging_file = common.MakeTempFile(suffix='.zip')
-  else:
-    staging_file = output_file
-
-  output_zip = zipfile.ZipFile(
-      staging_file, "w", compression=zipfile.ZIP_DEFLATED)
-
-  device_specific = common.DeviceSpecificParams(
-      input_zip=input_zip,
-      input_version=target_api_version,
-      output_zip=output_zip,
-      script=script,
-      input_tmp=OPTIONS.input_tmp,
-      metadata=metadata,
-      info_dict=OPTIONS.info_dict)
-
-  assert HasRecoveryPatch(input_zip, info_dict=OPTIONS.info_dict)
-
-  # Assertions (e.g. downgrade check, device properties check).
-  ts = target_info.GetBuildProp("ro.build.date.utc")
-  ts_text = target_info.GetBuildProp("ro.build.date")
-  script.AssertOlderBuild(ts, ts_text)
-
-  target_info.WriteDeviceAssertions(script, OPTIONS.oem_no_mount)
-  device_specific.FullOTA_Assertions()
-
-  block_diff_dict = GetBlockDifferences(target_zip=input_zip, source_zip=None,
-                                        target_info=target_info,
-                                        source_info=None,
-                                        device_specific=device_specific)
-
-  # Two-step package strategy (in chronological order, which is *not*
-  # the order in which the generated script has things):
-  #
-  # if stage is not "2/3" or "3/3":
-  #    write recovery image to boot partition
-  #    set stage to "2/3"
-  #    reboot to boot partition and restart recovery
-  # else if stage is "2/3":
-  #    write recovery image to recovery partition
-  #    set stage to "3/3"
-  #    reboot to recovery partition and restart recovery
-  # else:
-  #    (stage must be "3/3")
-  #    set stage to ""
-  #    do normal full package installation:
-  #       wipe and install system, boot image, etc.
-  #       set up system to update recovery partition on first boot
-  #    complete script normally
-  #    (allow recovery to mark itself finished and reboot)
-
-  recovery_img = common.GetBootableImage("recovery.img", "recovery.img",
-                                         OPTIONS.input_tmp, "RECOVERY")
-  if OPTIONS.two_step:
-    if not target_info.get("multistage_support"):
-      assert False, "two-step packages not supported by this build"
-    fs = target_info["fstab"]["/misc"]
-    assert fs.fs_type.upper() == "EMMC", \
-        "two-step packages only supported on devices with EMMC /misc partitions"
-    bcb_dev = {"bcb_dev": fs.device}
-    common.ZipWriteStr(output_zip, "recovery.img", recovery_img.data)
-    script.AppendExtra("""
-if get_stage("%(bcb_dev)s") == "2/3" then
-""" % bcb_dev)
-
-    # Stage 2/3: Write recovery image to /recovery (currently running /boot).
-    script.Comment("Stage 2/3")
-    script.WriteRawImage("/recovery", "recovery.img")
-    script.AppendExtra("""
-set_stage("%(bcb_dev)s", "3/3");
-reboot_now("%(bcb_dev)s", "recovery");
-else if get_stage("%(bcb_dev)s") == "3/3" then
-""" % bcb_dev)
-
-    # Stage 3/3: Make changes.
-    script.Comment("Stage 3/3")
-
-  # Dump fingerprints
-  script.Print("Target: {}".format(target_info.fingerprint))
-
-  device_specific.FullOTA_InstallBegin()
-
-  # All other partitions as well as the data wipe use 10% of the progress, and
-  # the update of the system partition takes the remaining progress.
-  system_progress = 0.9 - (len(block_diff_dict) - 1) * 0.1
-  if OPTIONS.wipe_user_data:
-    system_progress -= 0.1
-  progress_dict = {partition: 0.1 for partition in block_diff_dict}
-  progress_dict["system"] = system_progress
-
-  if target_info.get('use_dynamic_partitions') == "true":
-    # Use empty source_info_dict to indicate that all partitions / groups must
-    # be re-added.
-    dynamic_partitions_diff = common.DynamicPartitionsDifference(
-        info_dict=OPTIONS.info_dict,
-        block_diffs=block_diff_dict.values(),
-        progress_dict=progress_dict)
-    dynamic_partitions_diff.WriteScript(script, output_zip,
-                                        write_verify_script=OPTIONS.verify)
-  else:
-    for block_diff in block_diff_dict.values():
-      block_diff.WriteScript(script, output_zip,
-                             progress=progress_dict.get(block_diff.partition),
-                             write_verify_script=OPTIONS.verify)
-
-  CheckVintfIfTrebleEnabled(OPTIONS.input_tmp, target_info)
-
-  boot_img = common.GetBootableImage(
-      "boot.img", "boot.img", OPTIONS.input_tmp, "BOOT")
-  common.CheckSize(boot_img.data, "boot.img", target_info)
-  common.ZipWriteStr(output_zip, "boot.img", boot_img.data)
-
-  script.WriteRawImage("/boot", "boot.img")
-
-  script.ShowProgress(0.1, 10)
-  device_specific.FullOTA_InstallEnd()
-
-  if OPTIONS.extra_script is not None:
-    script.AppendExtra(OPTIONS.extra_script)
-
-  script.UnmountAll()
-
-  if OPTIONS.wipe_user_data:
-    script.ShowProgress(0.1, 10)
-    script.FormatPartition("/data")
-
-  if OPTIONS.two_step:
-    script.AppendExtra("""
-set_stage("%(bcb_dev)s", "");
-""" % bcb_dev)
-    script.AppendExtra("else\n")
-
-    # Stage 1/3: Nothing to verify for full OTA. Write recovery image to /boot.
-    script.Comment("Stage 1/3")
-    _WriteRecoveryImageToBoot(script, output_zip)
-
-    script.AppendExtra("""
-set_stage("%(bcb_dev)s", "2/3");
-reboot_now("%(bcb_dev)s", "");
-endif;
-endif;
-""" % bcb_dev)
-
-  script.SetProgress(1)
-  script.AddToZip(input_zip, output_zip, input_path=OPTIONS.updater_binary)
-  metadata["ota-required-cache"] = str(script.required_cache)
-
-  # We haven't written the metadata entry, which will be done in
-  # FinalizeMetadata.
-  common.ZipClose(output_zip)
-
-  needed_property_files = (
-      NonAbOtaPropertyFiles(),
-  )
-  FinalizeMetadata(metadata, staging_file, output_file, needed_property_files)
-
-
-def WriteMetadata(metadata, output):
-  """Writes the metadata to the zip archive or a file.
-
-  Args:
-    metadata: The metadata dict for the package.
-    output: A ZipFile object or a string of the output file path.
-  """
-
-  value = "".join(["%s=%s\n" % kv for kv in sorted(metadata.items())])
-  if isinstance(output, zipfile.ZipFile):
-    common.ZipWriteStr(output, METADATA_NAME, value,
-                       compress_type=zipfile.ZIP_STORED)
-    return
-
-  with open(output, 'w') as f:
-    f.write(value)
-
-
-def HandleDowngradeMetadata(metadata, target_info, source_info):
-  # Only incremental OTAs are allowed to reach here.
-  assert OPTIONS.incremental_source is not None
-
-  post_timestamp = target_info.GetBuildProp("ro.build.date.utc")
-  pre_timestamp = source_info.GetBuildProp("ro.build.date.utc")
-  is_downgrade = int(post_timestamp) < int(pre_timestamp)
-
-  if OPTIONS.downgrade:
-    if not is_downgrade:
-      raise RuntimeError(
-          "--downgrade or --override_timestamp specified but no downgrade "
-          "detected: pre: %s, post: %s" % (pre_timestamp, post_timestamp))
-    metadata["ota-downgrade"] = "yes"
-  else:
-    if is_downgrade:
-      raise RuntimeError(
-          "Downgrade detected based on timestamp check: pre: %s, post: %s. "
-          "Need to specify --override_timestamp OR --downgrade to allow "
-          "building the incremental." % (pre_timestamp, post_timestamp))
-
-
-def GetPackageMetadata(target_info, source_info=None):
-  """Generates and returns the metadata dict.
-
-  It generates a dict() that contains the info to be written into an OTA
-  package (META-INF/com/android/metadata). It also handles the detection of
-  downgrade / data wipe based on the global options.
-
-  Args:
-    target_info: The BuildInfo instance that holds the target build info.
-    source_info: The BuildInfo instance that holds the source build info, or
-        None if generating full OTA.
-
-  Returns:
-    A dict to be written into package metadata entry.
-  """
-  assert isinstance(target_info, common.BuildInfo)
-  assert source_info is None or isinstance(source_info, common.BuildInfo)
-
-  separator = '|'
-
-  boot_variable_values = {}
-  if OPTIONS.boot_variable_file:
-    d = common.LoadDictionaryFromFile(OPTIONS.boot_variable_file)
-    for key, values in d.items():
-      boot_variable_values[key] = [val.strip() for val in values.split(',')]
-
-  post_build_devices, post_build_fingerprints = \
-      CalculateRuntimeDevicesAndFingerprints(target_info, boot_variable_values)
-  metadata = {
-      'post-build': separator.join(sorted(post_build_fingerprints)),
-      'post-build-incremental': target_info.GetBuildProp(
-          'ro.build.version.incremental'),
-      'post-sdk-level': target_info.GetBuildProp(
-          'ro.build.version.sdk'),
-      'post-security-patch-level': target_info.GetBuildProp(
-          'ro.build.version.security_patch'),
-  }
-
-  if target_info.is_ab and not OPTIONS.force_non_ab:
-    metadata['ota-type'] = 'AB'
-    metadata['ota-required-cache'] = '0'
-  else:
-    metadata['ota-type'] = 'BLOCK'
-
-  if OPTIONS.wipe_user_data:
-    metadata['ota-wipe'] = 'yes'
-
-  if OPTIONS.retrofit_dynamic_partitions:
-    metadata['ota-retrofit-dynamic-partitions'] = 'yes'
-
-  is_incremental = source_info is not None
-  if is_incremental:
-    pre_build_devices, pre_build_fingerprints = \
-        CalculateRuntimeDevicesAndFingerprints(source_info,
-                                               boot_variable_values)
-    metadata['pre-build'] = separator.join(sorted(pre_build_fingerprints))
-    metadata['pre-build-incremental'] = source_info.GetBuildProp(
-        'ro.build.version.incremental')
-    metadata['pre-device'] = separator.join(sorted(pre_build_devices))
-  else:
-    metadata['pre-device'] = separator.join(sorted(post_build_devices))
-
-  # Use the actual post-timestamp, even for a downgrade case.
-  metadata['post-timestamp'] = target_info.GetBuildProp('ro.build.date.utc')
-
-  # Detect downgrades and set up downgrade flags accordingly.
-  if is_incremental:
-    HandleDowngradeMetadata(metadata, target_info, source_info)
-
-  return metadata
-
-
-class PropertyFiles(object):
-  """A class that computes the property-files string for an OTA package.
-
-  A property-files string is a comma-separated string that contains the
-  offset/size info for an OTA package. The entries, which must be ZIP_STORED,
-  can be fetched directly with the package URL along with the offset/size info.
-  These strings can be used for streaming A/B OTAs, or allowing an updater to
-  download package metadata entry directly, without paying the cost of
-  downloading entire package.
-
-  Computing the final property-files string requires two passes. Because doing
-  the whole package signing (with signapk.jar) will possibly reorder the ZIP
-  entries, which may in turn invalidate earlier computed ZIP entry offset/size
-  values.
-
-  This class provides functions to be called for each pass. The general flow is
-  as follows.
-
-    property_files = PropertyFiles()
-    # The first pass, which writes placeholders before doing initial signing.
-    property_files.Compute()
-    SignOutput()
-
-    # The second pass, by replacing the placeholders with actual data.
-    property_files.Finalize()
-    SignOutput()
-
-  And the caller can additionally verify the final result.
-
-    property_files.Verify()
-  """
-
-  def __init__(self):
-    self.name = None
-    self.required = ()
-    self.optional = ()
-
-  def Compute(self, input_zip):
-    """Computes and returns a property-files string with placeholders.
-
-    We reserve extra space for the offset and size of the metadata entry itself,
-    although we don't know the final values until the package gets signed.
-
-    Args:
-      input_zip: The input ZIP file.
-
-    Returns:
-      A string with placeholders for the metadata offset/size info, e.g.
-      "payload.bin:679:343,payload_properties.txt:378:45,metadata:        ".
-    """
-    return self.GetPropertyFilesString(input_zip, reserve_space=True)
-
-  class InsufficientSpaceException(Exception):
-    pass
-
-  def Finalize(self, input_zip, reserved_length):
-    """Finalizes a property-files string with actual METADATA offset/size info.
-
-    The input ZIP file has been signed, with the ZIP entries in the desired
-    place (signapk.jar will possibly reorder the ZIP entries). Now we compute
-    the ZIP entry offsets and construct the property-files string with actual
-    data. Note that during this process, we must pad the property-files string
-    to the reserved length, so that the METADATA entry size remains the same.
-    Otherwise the entries' offsets and sizes may change again.
-
-    Args:
-      input_zip: The input ZIP file.
-      reserved_length: The reserved length of the property-files string during
-          the call to Compute(). The final string must be no more than this
-          size.
-
-    Returns:
-      A property-files string including the metadata offset/size info, e.g.
-      "payload.bin:679:343,payload_properties.txt:378:45,metadata:69:379  ".
-
-    Raises:
-      InsufficientSpaceException: If the reserved length is insufficient to hold
-          the final string.
-    """
-    result = self.GetPropertyFilesString(input_zip, reserve_space=False)
-    if len(result) > reserved_length:
-      raise self.InsufficientSpaceException(
-          'Insufficient reserved space: reserved={}, actual={}'.format(
-              reserved_length, len(result)))
-
-    result += ' ' * (reserved_length - len(result))
-    return result
-
-  def Verify(self, input_zip, expected):
-    """Verifies the input ZIP file contains the expected property-files string.
-
-    Args:
-      input_zip: The input ZIP file.
-      expected: The property-files string that's computed from Finalize().
-
-    Raises:
-      AssertionError: On finding a mismatch.
-    """
-    actual = self.GetPropertyFilesString(input_zip)
-    assert actual == expected, \
-        "Mismatching streaming metadata: {} vs {}.".format(actual, expected)
-
-  def GetPropertyFilesString(self, zip_file, reserve_space=False):
-    """
-    Constructs the property-files string per request.
-
-    Args:
-      zip_file: The input ZIP file.
-      reserved_length: The reserved length of the property-files string.
-
-    Returns:
-      A property-files string including the metadata offset/size info, e.g.
-      "payload.bin:679:343,payload_properties.txt:378:45,metadata:     ".
-    """
-
-    def ComputeEntryOffsetSize(name):
-      """Computes the zip entry offset and size."""
-      info = zip_file.getinfo(name)
-      offset = info.header_offset
-      offset += zipfile.sizeFileHeader
-      offset += len(info.extra) + len(info.filename)
-      size = info.file_size
-      return '%s:%d:%d' % (os.path.basename(name), offset, size)
-
-    tokens = []
-    tokens.extend(self._GetPrecomputed(zip_file))
-    for entry in self.required:
-      tokens.append(ComputeEntryOffsetSize(entry))
-    for entry in self.optional:
-      if entry in zip_file.namelist():
-        tokens.append(ComputeEntryOffsetSize(entry))
-
-    # 'META-INF/com/android/metadata' is required. We don't know its actual
-    # offset and length (as well as the values for other entries). So we reserve
-    # 15-byte as a placeholder ('offset:length'), which is sufficient to cover
-    # the space for metadata entry. Because 'offset' allows a max of 10-digit
-    # (i.e. ~9 GiB), with a max of 4-digit for the length. Note that all the
-    # reserved space serves the metadata entry only.
-    if reserve_space:
-      tokens.append('metadata:' + ' ' * 15)
-    else:
-      tokens.append(ComputeEntryOffsetSize(METADATA_NAME))
-
-    return ','.join(tokens)
-
-  def _GetPrecomputed(self, input_zip):
-    """Computes the additional tokens to be included into the property-files.
-
-    This applies to tokens without actual ZIP entries, such as
-    payload_metadadata.bin. We want to expose the offset/size to updaters, so
-    that they can download the payload metadata directly with the info.
-
-    Args:
-      input_zip: The input zip file.
-
-    Returns:
-      A list of strings (tokens) to be added to the property-files string.
-    """
-    # pylint: disable=no-self-use
-    # pylint: disable=unused-argument
-    return []
-
-
 class StreamingPropertyFiles(PropertyFiles):
   """A subclass for computing the property-files for streaming A/B OTAs."""
 
@@ -1264,362 +601,6 @@
     return (payload_offset, metadata_total)
 
 
-class NonAbOtaPropertyFiles(PropertyFiles):
-  """The property-files for non-A/B OTA.
-
-  For non-A/B OTA, the property-files string contains the info for METADATA
-  entry, with which a system updater can be fetched the package metadata prior
-  to downloading the entire package.
-  """
-
-  def __init__(self):
-    super(NonAbOtaPropertyFiles, self).__init__()
-    self.name = 'ota-property-files'
-
-
-def FinalizeMetadata(metadata, input_file, output_file, needed_property_files):
-  """Finalizes the metadata and signs an A/B OTA package.
-
-  In order to stream an A/B OTA package, we need 'ota-streaming-property-files'
-  that contains the offsets and sizes for the ZIP entries. An example
-  property-files string is as follows.
-
-    "payload.bin:679:343,payload_properties.txt:378:45,metadata:69:379"
-
-  OTA server can pass down this string, in addition to the package URL, to the
-  system update client. System update client can then fetch individual ZIP
-  entries (ZIP_STORED) directly at the given offset of the URL.
-
-  Args:
-    metadata: The metadata dict for the package.
-    input_file: The input ZIP filename that doesn't contain the package METADATA
-        entry yet.
-    output_file: The final output ZIP filename.
-    needed_property_files: The list of PropertyFiles' to be generated.
-  """
-
-  def ComputeAllPropertyFiles(input_file, needed_property_files):
-    # Write the current metadata entry with placeholders.
-    with zipfile.ZipFile(input_file) as input_zip:
-      for property_files in needed_property_files:
-        metadata[property_files.name] = property_files.Compute(input_zip)
-      namelist = input_zip.namelist()
-
-    if METADATA_NAME in namelist:
-      common.ZipDelete(input_file, METADATA_NAME)
-    output_zip = zipfile.ZipFile(input_file, 'a')
-    WriteMetadata(metadata, output_zip)
-    common.ZipClose(output_zip)
-
-    if OPTIONS.no_signing:
-      return input_file
-
-    prelim_signing = common.MakeTempFile(suffix='.zip')
-    SignOutput(input_file, prelim_signing)
-    return prelim_signing
-
-  def FinalizeAllPropertyFiles(prelim_signing, needed_property_files):
-    with zipfile.ZipFile(prelim_signing) as prelim_signing_zip:
-      for property_files in needed_property_files:
-        metadata[property_files.name] = property_files.Finalize(
-            prelim_signing_zip, len(metadata[property_files.name]))
-
-  # SignOutput(), which in turn calls signapk.jar, will possibly reorder the ZIP
-  # entries, as well as padding the entry headers. We do a preliminary signing
-  # (with an incomplete metadata entry) to allow that to happen. Then compute
-  # the ZIP entry offsets, write back the final metadata and do the final
-  # signing.
-  prelim_signing = ComputeAllPropertyFiles(input_file, needed_property_files)
-  try:
-    FinalizeAllPropertyFiles(prelim_signing, needed_property_files)
-  except PropertyFiles.InsufficientSpaceException:
-    # Even with the preliminary signing, the entry orders may change
-    # dramatically, which leads to insufficiently reserved space during the
-    # first call to ComputeAllPropertyFiles(). In that case, we redo all the
-    # preliminary signing works, based on the already ordered ZIP entries, to
-    # address the issue.
-    prelim_signing = ComputeAllPropertyFiles(
-        prelim_signing, needed_property_files)
-    FinalizeAllPropertyFiles(prelim_signing, needed_property_files)
-
-  # Replace the METADATA entry.
-  common.ZipDelete(prelim_signing, METADATA_NAME)
-  output_zip = zipfile.ZipFile(prelim_signing, 'a')
-  WriteMetadata(metadata, output_zip)
-  common.ZipClose(output_zip)
-
-  # Re-sign the package after updating the metadata entry.
-  if OPTIONS.no_signing:
-    output_file = prelim_signing
-  else:
-    SignOutput(prelim_signing, output_file)
-
-  # Reopen the final signed zip to double check the streaming metadata.
-  with zipfile.ZipFile(output_file) as output_zip:
-    for property_files in needed_property_files:
-      property_files.Verify(output_zip, metadata[property_files.name].strip())
-
-  # If requested, dump the metadata to a separate file.
-  output_metadata_path = OPTIONS.output_metadata_path
-  if output_metadata_path:
-    WriteMetadata(metadata, output_metadata_path)
-
-
-def WriteBlockIncrementalOTAPackage(target_zip, source_zip, output_file):
-  target_info = common.BuildInfo(OPTIONS.target_info_dict, OPTIONS.oem_dicts)
-  source_info = common.BuildInfo(OPTIONS.source_info_dict, OPTIONS.oem_dicts)
-
-  target_api_version = target_info["recovery_api_version"]
-  source_api_version = source_info["recovery_api_version"]
-  if source_api_version == 0:
-    logger.warning(
-        "Generating edify script for a source that can't install it.")
-
-  script = edify_generator.EdifyGenerator(
-      source_api_version, target_info, fstab=source_info["fstab"])
-
-  if target_info.oem_props or source_info.oem_props:
-    if not OPTIONS.oem_no_mount:
-      source_info.WriteMountOemScript(script)
-
-  metadata = GetPackageMetadata(target_info, source_info)
-
-  if not OPTIONS.no_signing:
-    staging_file = common.MakeTempFile(suffix='.zip')
-  else:
-    staging_file = output_file
-
-  output_zip = zipfile.ZipFile(
-      staging_file, "w", compression=zipfile.ZIP_DEFLATED)
-
-  device_specific = common.DeviceSpecificParams(
-      source_zip=source_zip,
-      source_version=source_api_version,
-      source_tmp=OPTIONS.source_tmp,
-      target_zip=target_zip,
-      target_version=target_api_version,
-      target_tmp=OPTIONS.target_tmp,
-      output_zip=output_zip,
-      script=script,
-      metadata=metadata,
-      info_dict=source_info)
-
-  source_boot = common.GetBootableImage(
-      "/tmp/boot.img", "boot.img", OPTIONS.source_tmp, "BOOT", source_info)
-  target_boot = common.GetBootableImage(
-      "/tmp/boot.img", "boot.img", OPTIONS.target_tmp, "BOOT", target_info)
-  updating_boot = (not OPTIONS.two_step and
-                   (source_boot.data != target_boot.data))
-
-  target_recovery = common.GetBootableImage(
-      "/tmp/recovery.img", "recovery.img", OPTIONS.target_tmp, "RECOVERY")
-
-  block_diff_dict = GetBlockDifferences(target_zip=target_zip,
-                                        source_zip=source_zip,
-                                        target_info=target_info,
-                                        source_info=source_info,
-                                        device_specific=device_specific)
-
-  CheckVintfIfTrebleEnabled(OPTIONS.target_tmp, target_info)
-
-  # Assertions (e.g. device properties check).
-  target_info.WriteDeviceAssertions(script, OPTIONS.oem_no_mount)
-  device_specific.IncrementalOTA_Assertions()
-
-  # Two-step incremental package strategy (in chronological order,
-  # which is *not* the order in which the generated script has
-  # things):
-  #
-  # if stage is not "2/3" or "3/3":
-  #    do verification on current system
-  #    write recovery image to boot partition
-  #    set stage to "2/3"
-  #    reboot to boot partition and restart recovery
-  # else if stage is "2/3":
-  #    write recovery image to recovery partition
-  #    set stage to "3/3"
-  #    reboot to recovery partition and restart recovery
-  # else:
-  #    (stage must be "3/3")
-  #    perform update:
-  #       patch system files, etc.
-  #       force full install of new boot image
-  #       set up system to update recovery partition on first boot
-  #    complete script normally
-  #    (allow recovery to mark itself finished and reboot)
-
-  if OPTIONS.two_step:
-    if not source_info.get("multistage_support"):
-      assert False, "two-step packages not supported by this build"
-    fs = source_info["fstab"]["/misc"]
-    assert fs.fs_type.upper() == "EMMC", \
-        "two-step packages only supported on devices with EMMC /misc partitions"
-    bcb_dev = {"bcb_dev": fs.device}
-    common.ZipWriteStr(output_zip, "recovery.img", target_recovery.data)
-    script.AppendExtra("""
-if get_stage("%(bcb_dev)s") == "2/3" then
-""" % bcb_dev)
-
-    # Stage 2/3: Write recovery image to /recovery (currently running /boot).
-    script.Comment("Stage 2/3")
-    script.AppendExtra("sleep(20);\n")
-    script.WriteRawImage("/recovery", "recovery.img")
-    script.AppendExtra("""
-set_stage("%(bcb_dev)s", "3/3");
-reboot_now("%(bcb_dev)s", "recovery");
-else if get_stage("%(bcb_dev)s") != "3/3" then
-""" % bcb_dev)
-
-    # Stage 1/3: (a) Verify the current system.
-    script.Comment("Stage 1/3")
-
-  # Dump fingerprints
-  script.Print("Source: {}".format(source_info.fingerprint))
-  script.Print("Target: {}".format(target_info.fingerprint))
-
-  script.Print("Verifying current system...")
-
-  device_specific.IncrementalOTA_VerifyBegin()
-
-  WriteFingerprintAssertion(script, target_info, source_info)
-
-  # Check the required cache size (i.e. stashed blocks).
-  required_cache_sizes = [diff.required_cache for diff in
-                          block_diff_dict.values()]
-  if updating_boot:
-    boot_type, boot_device_expr = common.GetTypeAndDeviceExpr("/boot",
-                                                              source_info)
-    d = common.Difference(target_boot, source_boot)
-    _, _, d = d.ComputePatch()
-    if d is None:
-      include_full_boot = True
-      common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
-    else:
-      include_full_boot = False
-
-      logger.info(
-          "boot      target: %d  source: %d  diff: %d", target_boot.size,
-          source_boot.size, len(d))
-
-      common.ZipWriteStr(output_zip, "boot.img.p", d)
-
-      target_expr = 'concat("{}:",{},":{}:{}")'.format(
-          boot_type, boot_device_expr, target_boot.size, target_boot.sha1)
-      source_expr = 'concat("{}:",{},":{}:{}")'.format(
-          boot_type, boot_device_expr, source_boot.size, source_boot.sha1)
-      script.PatchPartitionExprCheck(target_expr, source_expr)
-
-      required_cache_sizes.append(target_boot.size)
-
-  if required_cache_sizes:
-    script.CacheFreeSpaceCheck(max(required_cache_sizes))
-
-  # Verify the existing partitions.
-  for diff in block_diff_dict.values():
-    diff.WriteVerifyScript(script, touched_blocks_only=True)
-
-  device_specific.IncrementalOTA_VerifyEnd()
-
-  if OPTIONS.two_step:
-    # Stage 1/3: (b) Write recovery image to /boot.
-    _WriteRecoveryImageToBoot(script, output_zip)
-
-    script.AppendExtra("""
-set_stage("%(bcb_dev)s", "2/3");
-reboot_now("%(bcb_dev)s", "");
-else
-""" % bcb_dev)
-
-    # Stage 3/3: Make changes.
-    script.Comment("Stage 3/3")
-
-  script.Comment("---- start making changes here ----")
-
-  device_specific.IncrementalOTA_InstallBegin()
-
-  progress_dict = {partition: 0.1 for partition in block_diff_dict}
-  progress_dict["system"] = 1 - len(block_diff_dict) * 0.1
-
-  if OPTIONS.source_info_dict.get("use_dynamic_partitions") == "true":
-    if OPTIONS.target_info_dict.get("use_dynamic_partitions") != "true":
-      raise RuntimeError(
-          "can't generate incremental that disables dynamic partitions")
-    dynamic_partitions_diff = common.DynamicPartitionsDifference(
-        info_dict=OPTIONS.target_info_dict,
-        source_info_dict=OPTIONS.source_info_dict,
-        block_diffs=block_diff_dict.values(),
-        progress_dict=progress_dict)
-    dynamic_partitions_diff.WriteScript(
-        script, output_zip, write_verify_script=OPTIONS.verify)
-  else:
-    for block_diff in block_diff_dict.values():
-      block_diff.WriteScript(script, output_zip,
-                             progress=progress_dict.get(block_diff.partition),
-                             write_verify_script=OPTIONS.verify)
-
-  if OPTIONS.two_step:
-    common.ZipWriteStr(output_zip, "boot.img", target_boot.data)
-    script.WriteRawImage("/boot", "boot.img")
-    logger.info("writing full boot image (forced by two-step mode)")
-
-  if not OPTIONS.two_step:
-    if updating_boot:
-      if include_full_boot:
-        logger.info("boot image changed; including full.")
-        script.Print("Installing boot image...")
-        script.WriteRawImage("/boot", "boot.img")
-      else:
-        # Produce the boot image by applying a patch to the current
-        # contents of the boot partition, and write it back to the
-        # partition.
-        logger.info("boot image changed; including patch.")
-        script.Print("Patching boot image...")
-        script.ShowProgress(0.1, 10)
-        target_expr = 'concat("{}:",{},":{}:{}")'.format(
-            boot_type, boot_device_expr, target_boot.size, target_boot.sha1)
-        source_expr = 'concat("{}:",{},":{}:{}")'.format(
-            boot_type, boot_device_expr, source_boot.size, source_boot.sha1)
-        script.PatchPartitionExpr(target_expr, source_expr, '"boot.img.p"')
-    else:
-      logger.info("boot image unchanged; skipping.")
-
-  # Do device-specific installation (eg, write radio image).
-  device_specific.IncrementalOTA_InstallEnd()
-
-  if OPTIONS.extra_script is not None:
-    script.AppendExtra(OPTIONS.extra_script)
-
-  if OPTIONS.wipe_user_data:
-    script.Print("Erasing user data...")
-    script.FormatPartition("/data")
-
-  if OPTIONS.two_step:
-    script.AppendExtra("""
-set_stage("%(bcb_dev)s", "");
-endif;
-endif;
-""" % bcb_dev)
-
-  script.SetProgress(1)
-  # For downgrade OTAs, we prefer to use the update-binary in the source
-  # build that is actually newer than the one in the target build.
-  if OPTIONS.downgrade:
-    script.AddToZip(source_zip, output_zip, input_path=OPTIONS.updater_binary)
-  else:
-    script.AddToZip(target_zip, output_zip, input_path=OPTIONS.updater_binary)
-  metadata["ota-required-cache"] = str(script.required_cache)
-
-  # We haven't written the metadata entry yet, which will be handled in
-  # FinalizeMetadata().
-  common.ZipClose(output_zip)
-
-  # Sign the generated zip package unless no_signing is specified.
-  needed_property_files = (
-      NonAbOtaPropertyFiles(),
-  )
-  FinalizeMetadata(metadata, staging_file, output_file, needed_property_files)
-
-
 def GetTargetFilesZipForSecondaryImages(input_file, skip_postinstall=False):
   """Returns a target-files.zip file for generating secondary payload.
 
@@ -1938,104 +919,6 @@
   FinalizeMetadata(metadata, staging_file, output_file, needed_property_files)
 
 
-def GenerateNonAbOtaPackage(target_file, output_file, source_file=None):
-  """Generates a non-A/B OTA package."""
-  # Check the loaded info dicts first.
-  if OPTIONS.info_dict.get("no_recovery") == "true":
-    raise common.ExternalError(
-        "--- target build has specified no recovery ---")
-
-  # Non-A/B OTAs rely on /cache partition to store temporary files.
-  cache_size = OPTIONS.info_dict.get("cache_size")
-  if cache_size is None:
-    logger.warning("--- can't determine the cache partition size ---")
-  OPTIONS.cache_size = cache_size
-
-  if OPTIONS.extra_script is not None:
-    with open(OPTIONS.extra_script) as fp:
-      OPTIONS.extra_script = fp.read()
-
-  if OPTIONS.extracted_input is not None:
-    OPTIONS.input_tmp = OPTIONS.extracted_input
-  else:
-    logger.info("unzipping target target-files...")
-    OPTIONS.input_tmp = common.UnzipTemp(target_file, UNZIP_PATTERN)
-  OPTIONS.target_tmp = OPTIONS.input_tmp
-
-  # If the caller explicitly specified the device-specific extensions path via
-  # -s / --device_specific, use that. Otherwise, use META/releasetools.py if it
-  # is present in the target target_files. Otherwise, take the path of the file
-  # from 'tool_extensions' in the info dict and look for that in the local
-  # filesystem, relative to the current directory.
-  if OPTIONS.device_specific is None:
-    from_input = os.path.join(OPTIONS.input_tmp, "META", "releasetools.py")
-    if os.path.exists(from_input):
-      logger.info("(using device-specific extensions from target_files)")
-      OPTIONS.device_specific = from_input
-    else:
-      OPTIONS.device_specific = OPTIONS.info_dict.get("tool_extensions")
-
-  if OPTIONS.device_specific is not None:
-    OPTIONS.device_specific = os.path.abspath(OPTIONS.device_specific)
-
-  # Generate a full OTA.
-  if source_file is None:
-    with zipfile.ZipFile(target_file) as input_zip:
-      WriteFullOTAPackage(
-          input_zip,
-          output_file)
-
-  # Generate an incremental OTA.
-  else:
-    logger.info("unzipping source target-files...")
-    OPTIONS.source_tmp = common.UnzipTemp(
-        OPTIONS.incremental_source, UNZIP_PATTERN)
-    with zipfile.ZipFile(target_file) as input_zip, \
-            zipfile.ZipFile(source_file) as source_zip:
-      WriteBlockIncrementalOTAPackage(
-          input_zip,
-          source_zip,
-          output_file)
-
-
-def CalculateRuntimeDevicesAndFingerprints(build_info, boot_variable_values):
-  """Returns a tuple of sets for runtime devices and fingerprints"""
-
-  device_names = {build_info.device}
-  fingerprints = {build_info.fingerprint}
-
-  if not boot_variable_values:
-    return device_names, fingerprints
-
-  # Calculate all possible combinations of the values for the boot variables.
-  keys = boot_variable_values.keys()
-  value_list = boot_variable_values.values()
-  combinations = [dict(zip(keys, values))
-                  for values in itertools.product(*value_list)]
-  for placeholder_values in combinations:
-    # Reload the info_dict as some build properties may change their values
-    # based on the value of ro.boot* properties.
-    info_dict = copy.deepcopy(build_info.info_dict)
-    for partition in common.PARTITIONS_WITH_CARE_MAP:
-      partition_prop_key = "{}.build.prop".format(partition)
-      input_file = info_dict[partition_prop_key].input_file
-      if isinstance(input_file, zipfile.ZipFile):
-        with zipfile.ZipFile(input_file.filename) as input_zip:
-          info_dict[partition_prop_key] = \
-              common.PartitionBuildProps.FromInputFile(input_zip, partition,
-                                                       placeholder_values)
-      else:
-        info_dict[partition_prop_key] = \
-            common.PartitionBuildProps.FromInputFile(input_file, partition,
-                                                     placeholder_values)
-    info_dict["build.prop"] = info_dict["system.build.prop"]
-
-    new_build_info = common.BuildInfo(info_dict, build_info.oem_dicts)
-    device_names.add(new_build_info.device)
-    fingerprints.add(new_build_info.fingerprint)
-  return device_names, fingerprints
-
-
 def main(argv):
 
   def option_handler(o, a):
diff --git a/tools/releasetools/ota_utils.py b/tools/releasetools/ota_utils.py
new file mode 100644
index 0000000..874ab95
--- /dev/null
+++ b/tools/releasetools/ota_utils.py
@@ -0,0 +1,433 @@
+# Copyright (C) 2020 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.
+
+import copy
+import itertools
+import os
+import zipfile
+
+from common import (ZipDelete, ZipClose, OPTIONS, MakeTempFile,
+                    ZipWriteStr, BuildInfo, LoadDictionaryFromFile,
+                    SignFile, PARTITIONS_WITH_CARE_MAP, PartitionBuildProps)
+
+METADATA_NAME = 'META-INF/com/android/metadata'
+UNZIP_PATTERN = ['IMAGES/*', 'META/*', 'OTA/*', 'RADIO/*']
+
+
+def FinalizeMetadata(metadata, input_file, output_file, needed_property_files):
+  """Finalizes the metadata and signs an A/B OTA package.
+
+  In order to stream an A/B OTA package, we need 'ota-streaming-property-files'
+  that contains the offsets and sizes for the ZIP entries. An example
+  property-files string is as follows.
+
+    "payload.bin:679:343,payload_properties.txt:378:45,metadata:69:379"
+
+  OTA server can pass down this string, in addition to the package URL, to the
+  system update client. System update client can then fetch individual ZIP
+  entries (ZIP_STORED) directly at the given offset of the URL.
+
+  Args:
+    metadata: The metadata dict for the package.
+    input_file: The input ZIP filename that doesn't contain the package METADATA
+        entry yet.
+    output_file: The final output ZIP filename.
+    needed_property_files: The list of PropertyFiles' to be generated.
+  """
+
+  def ComputeAllPropertyFiles(input_file, needed_property_files):
+    # Write the current metadata entry with placeholders.
+    with zipfile.ZipFile(input_file) as input_zip:
+      for property_files in needed_property_files:
+        metadata[property_files.name] = property_files.Compute(input_zip)
+      namelist = input_zip.namelist()
+
+    if METADATA_NAME in namelist:
+      ZipDelete(input_file, METADATA_NAME)
+    output_zip = zipfile.ZipFile(input_file, 'a')
+    WriteMetadata(metadata, output_zip)
+    ZipClose(output_zip)
+
+    if OPTIONS.no_signing:
+      return input_file
+
+    prelim_signing = MakeTempFile(suffix='.zip')
+    SignOutput(input_file, prelim_signing)
+    return prelim_signing
+
+  def FinalizeAllPropertyFiles(prelim_signing, needed_property_files):
+    with zipfile.ZipFile(prelim_signing) as prelim_signing_zip:
+      for property_files in needed_property_files:
+        metadata[property_files.name] = property_files.Finalize(
+            prelim_signing_zip, len(metadata[property_files.name]))
+
+  # SignOutput(), which in turn calls signapk.jar, will possibly reorder the ZIP
+  # entries, as well as padding the entry headers. We do a preliminary signing
+  # (with an incomplete metadata entry) to allow that to happen. Then compute
+  # the ZIP entry offsets, write back the final metadata and do the final
+  # signing.
+  prelim_signing = ComputeAllPropertyFiles(input_file, needed_property_files)
+  try:
+    FinalizeAllPropertyFiles(prelim_signing, needed_property_files)
+  except PropertyFiles.InsufficientSpaceException:
+    # Even with the preliminary signing, the entry orders may change
+    # dramatically, which leads to insufficiently reserved space during the
+    # first call to ComputeAllPropertyFiles(). In that case, we redo all the
+    # preliminary signing works, based on the already ordered ZIP entries, to
+    # address the issue.
+    prelim_signing = ComputeAllPropertyFiles(
+        prelim_signing, needed_property_files)
+    FinalizeAllPropertyFiles(prelim_signing, needed_property_files)
+
+  # Replace the METADATA entry.
+  ZipDelete(prelim_signing, METADATA_NAME)
+  output_zip = zipfile.ZipFile(prelim_signing, 'a')
+  WriteMetadata(metadata, output_zip)
+  ZipClose(output_zip)
+
+  # Re-sign the package after updating the metadata entry.
+  if OPTIONS.no_signing:
+    output_file = prelim_signing
+  else:
+    SignOutput(prelim_signing, output_file)
+
+  # Reopen the final signed zip to double check the streaming metadata.
+  with zipfile.ZipFile(output_file) as output_zip:
+    for property_files in needed_property_files:
+      property_files.Verify(output_zip, metadata[property_files.name].strip())
+
+  # If requested, dump the metadata to a separate file.
+  output_metadata_path = OPTIONS.output_metadata_path
+  if output_metadata_path:
+    WriteMetadata(metadata, output_metadata_path)
+
+
+def WriteMetadata(metadata, output):
+  """Writes the metadata to the zip archive or a file.
+
+  Args:
+    metadata: The metadata dict for the package.
+    output: A ZipFile object or a string of the output file path.
+  """
+
+  value = "".join(["%s=%s\n" % kv for kv in sorted(metadata.items())])
+  if isinstance(output, zipfile.ZipFile):
+    ZipWriteStr(output, METADATA_NAME, value,
+                compress_type=zipfile.ZIP_STORED)
+    return
+
+  with open(output, 'w') as f:
+    f.write(value)
+
+
+def GetPackageMetadata(target_info, source_info=None):
+  """Generates and returns the metadata dict.
+
+  It generates a dict() that contains the info to be written into an OTA
+  package (META-INF/com/android/metadata). It also handles the detection of
+  downgrade / data wipe based on the global options.
+
+  Args:
+    target_info: The BuildInfo instance that holds the target build info.
+    source_info: The BuildInfo instance that holds the source build info, or
+        None if generating full OTA.
+
+  Returns:
+    A dict to be written into package metadata entry.
+  """
+  assert isinstance(target_info, BuildInfo)
+  assert source_info is None or isinstance(source_info, BuildInfo)
+
+  separator = '|'
+
+  boot_variable_values = {}
+  if OPTIONS.boot_variable_file:
+    d = LoadDictionaryFromFile(OPTIONS.boot_variable_file)
+    for key, values in d.items():
+      boot_variable_values[key] = [val.strip() for val in values.split(',')]
+
+  post_build_devices, post_build_fingerprints = \
+      CalculateRuntimeDevicesAndFingerprints(target_info, boot_variable_values)
+  metadata = {
+      'post-build': separator.join(sorted(post_build_fingerprints)),
+      'post-build-incremental': target_info.GetBuildProp(
+          'ro.build.version.incremental'),
+      'post-sdk-level': target_info.GetBuildProp(
+          'ro.build.version.sdk'),
+      'post-security-patch-level': target_info.GetBuildProp(
+          'ro.build.version.security_patch'),
+  }
+
+  if target_info.is_ab and not OPTIONS.force_non_ab:
+    metadata['ota-type'] = 'AB'
+    metadata['ota-required-cache'] = '0'
+  else:
+    metadata['ota-type'] = 'BLOCK'
+
+  if OPTIONS.wipe_user_data:
+    metadata['ota-wipe'] = 'yes'
+
+  if OPTIONS.retrofit_dynamic_partitions:
+    metadata['ota-retrofit-dynamic-partitions'] = 'yes'
+
+  is_incremental = source_info is not None
+  if is_incremental:
+    pre_build_devices, pre_build_fingerprints = \
+        CalculateRuntimeDevicesAndFingerprints(source_info,
+                                               boot_variable_values)
+    metadata['pre-build'] = separator.join(sorted(pre_build_fingerprints))
+    metadata['pre-build-incremental'] = source_info.GetBuildProp(
+        'ro.build.version.incremental')
+    metadata['pre-device'] = separator.join(sorted(pre_build_devices))
+  else:
+    metadata['pre-device'] = separator.join(sorted(post_build_devices))
+
+  # Use the actual post-timestamp, even for a downgrade case.
+  metadata['post-timestamp'] = target_info.GetBuildProp('ro.build.date.utc')
+
+  # Detect downgrades and set up downgrade flags accordingly.
+  if is_incremental:
+    HandleDowngradeMetadata(metadata, target_info, source_info)
+
+  return metadata
+
+
+def HandleDowngradeMetadata(metadata, target_info, source_info):
+  # Only incremental OTAs are allowed to reach here.
+  assert OPTIONS.incremental_source is not None
+
+  post_timestamp = target_info.GetBuildProp("ro.build.date.utc")
+  pre_timestamp = source_info.GetBuildProp("ro.build.date.utc")
+  is_downgrade = int(post_timestamp) < int(pre_timestamp)
+
+  if OPTIONS.downgrade:
+    if not is_downgrade:
+      raise RuntimeError(
+          "--downgrade or --override_timestamp specified but no downgrade "
+          "detected: pre: %s, post: %s" % (pre_timestamp, post_timestamp))
+    metadata["ota-downgrade"] = "yes"
+  else:
+    if is_downgrade:
+      raise RuntimeError(
+          "Downgrade detected based on timestamp check: pre: %s, post: %s. "
+          "Need to specify --override_timestamp OR --downgrade to allow "
+          "building the incremental." % (pre_timestamp, post_timestamp))
+
+
+def CalculateRuntimeDevicesAndFingerprints(build_info, boot_variable_values):
+  """Returns a tuple of sets for runtime devices and fingerprints"""
+
+  device_names = {build_info.device}
+  fingerprints = {build_info.fingerprint}
+
+  if not boot_variable_values:
+    return device_names, fingerprints
+
+  # Calculate all possible combinations of the values for the boot variables.
+  keys = boot_variable_values.keys()
+  value_list = boot_variable_values.values()
+  combinations = [dict(zip(keys, values))
+                  for values in itertools.product(*value_list)]
+  for placeholder_values in combinations:
+    # Reload the info_dict as some build properties may change their values
+    # based on the value of ro.boot* properties.
+    info_dict = copy.deepcopy(build_info.info_dict)
+    for partition in PARTITIONS_WITH_CARE_MAP:
+      partition_prop_key = "{}.build.prop".format(partition)
+      input_file = info_dict[partition_prop_key].input_file
+      if isinstance(input_file, zipfile.ZipFile):
+        with zipfile.ZipFile(input_file.filename) as input_zip:
+          info_dict[partition_prop_key] = \
+              PartitionBuildProps.FromInputFile(input_zip, partition,
+                                                placeholder_values)
+      else:
+        info_dict[partition_prop_key] = \
+            PartitionBuildProps.FromInputFile(input_file, partition,
+                                              placeholder_values)
+    info_dict["build.prop"] = info_dict["system.build.prop"]
+
+    new_build_info = BuildInfo(info_dict, build_info.oem_dicts)
+    device_names.add(new_build_info.device)
+    fingerprints.add(new_build_info.fingerprint)
+  return device_names, fingerprints
+
+
+class PropertyFiles(object):
+  """A class that computes the property-files string for an OTA package.
+
+  A property-files string is a comma-separated string that contains the
+  offset/size info for an OTA package. The entries, which must be ZIP_STORED,
+  can be fetched directly with the package URL along with the offset/size info.
+  These strings can be used for streaming A/B OTAs, or allowing an updater to
+  download package metadata entry directly, without paying the cost of
+  downloading entire package.
+
+  Computing the final property-files string requires two passes. Because doing
+  the whole package signing (with signapk.jar) will possibly reorder the ZIP
+  entries, which may in turn invalidate earlier computed ZIP entry offset/size
+  values.
+
+  This class provides functions to be called for each pass. The general flow is
+  as follows.
+
+    property_files = PropertyFiles()
+    # The first pass, which writes placeholders before doing initial signing.
+    property_files.Compute()
+    SignOutput()
+
+    # The second pass, by replacing the placeholders with actual data.
+    property_files.Finalize()
+    SignOutput()
+
+  And the caller can additionally verify the final result.
+
+    property_files.Verify()
+  """
+
+  def __init__(self):
+    self.name = None
+    self.required = ()
+    self.optional = ()
+
+  def Compute(self, input_zip):
+    """Computes and returns a property-files string with placeholders.
+
+    We reserve extra space for the offset and size of the metadata entry itself,
+    although we don't know the final values until the package gets signed.
+
+    Args:
+      input_zip: The input ZIP file.
+
+    Returns:
+      A string with placeholders for the metadata offset/size info, e.g.
+      "payload.bin:679:343,payload_properties.txt:378:45,metadata:        ".
+    """
+    return self.GetPropertyFilesString(input_zip, reserve_space=True)
+
+  class InsufficientSpaceException(Exception):
+    pass
+
+  def Finalize(self, input_zip, reserved_length):
+    """Finalizes a property-files string with actual METADATA offset/size info.
+
+    The input ZIP file has been signed, with the ZIP entries in the desired
+    place (signapk.jar will possibly reorder the ZIP entries). Now we compute
+    the ZIP entry offsets and construct the property-files string with actual
+    data. Note that during this process, we must pad the property-files string
+    to the reserved length, so that the METADATA entry size remains the same.
+    Otherwise the entries' offsets and sizes may change again.
+
+    Args:
+      input_zip: The input ZIP file.
+      reserved_length: The reserved length of the property-files string during
+          the call to Compute(). The final string must be no more than this
+          size.
+
+    Returns:
+      A property-files string including the metadata offset/size info, e.g.
+      "payload.bin:679:343,payload_properties.txt:378:45,metadata:69:379  ".
+
+    Raises:
+      InsufficientSpaceException: If the reserved length is insufficient to hold
+          the final string.
+    """
+    result = self.GetPropertyFilesString(input_zip, reserve_space=False)
+    if len(result) > reserved_length:
+      raise self.InsufficientSpaceException(
+          'Insufficient reserved space: reserved={}, actual={}'.format(
+              reserved_length, len(result)))
+
+    result += ' ' * (reserved_length - len(result))
+    return result
+
+  def Verify(self, input_zip, expected):
+    """Verifies the input ZIP file contains the expected property-files string.
+
+    Args:
+      input_zip: The input ZIP file.
+      expected: The property-files string that's computed from Finalize().
+
+    Raises:
+      AssertionError: On finding a mismatch.
+    """
+    actual = self.GetPropertyFilesString(input_zip)
+    assert actual == expected, \
+        "Mismatching streaming metadata: {} vs {}.".format(actual, expected)
+
+  def GetPropertyFilesString(self, zip_file, reserve_space=False):
+    """
+    Constructs the property-files string per request.
+
+    Args:
+      zip_file: The input ZIP file.
+      reserved_length: The reserved length of the property-files string.
+
+    Returns:
+      A property-files string including the metadata offset/size info, e.g.
+      "payload.bin:679:343,payload_properties.txt:378:45,metadata:     ".
+    """
+
+    def ComputeEntryOffsetSize(name):
+      """Computes the zip entry offset and size."""
+      info = zip_file.getinfo(name)
+      offset = info.header_offset
+      offset += zipfile.sizeFileHeader
+      offset += len(info.extra) + len(info.filename)
+      size = info.file_size
+      return '%s:%d:%d' % (os.path.basename(name), offset, size)
+
+    tokens = []
+    tokens.extend(self._GetPrecomputed(zip_file))
+    for entry in self.required:
+      tokens.append(ComputeEntryOffsetSize(entry))
+    for entry in self.optional:
+      if entry in zip_file.namelist():
+        tokens.append(ComputeEntryOffsetSize(entry))
+
+    # 'META-INF/com/android/metadata' is required. We don't know its actual
+    # offset and length (as well as the values for other entries). So we reserve
+    # 15-byte as a placeholder ('offset:length'), which is sufficient to cover
+    # the space for metadata entry. Because 'offset' allows a max of 10-digit
+    # (i.e. ~9 GiB), with a max of 4-digit for the length. Note that all the
+    # reserved space serves the metadata entry only.
+    if reserve_space:
+      tokens.append('metadata:' + ' ' * 15)
+    else:
+      tokens.append(ComputeEntryOffsetSize(METADATA_NAME))
+
+    return ','.join(tokens)
+
+  def _GetPrecomputed(self, input_zip):
+    """Computes the additional tokens to be included into the property-files.
+
+    This applies to tokens without actual ZIP entries, such as
+    payload_metadata.bin. We want to expose the offset/size to updaters, so
+    that they can download the payload metadata directly with the info.
+
+    Args:
+      input_zip: The input zip file.
+
+    Returns:
+      A list of strings (tokens) to be added to the property-files string.
+    """
+    # pylint: disable=no-self-use
+    # pylint: disable=unused-argument
+    return []
+
+
+def SignOutput(temp_zip_name, output_zip_name):
+  pw = OPTIONS.key_passwords[OPTIONS.package_key]
+
+  SignFile(temp_zip_name, output_zip_name, OPTIONS.package_key, pw,
+           whole_file=True)
diff --git a/tools/releasetools/test_non_ab_ota.py b/tools/releasetools/test_non_ab_ota.py
new file mode 100644
index 0000000..ee1b411
--- /dev/null
+++ b/tools/releasetools/test_non_ab_ota.py
@@ -0,0 +1,169 @@
+#
+# Copyright (C) 2020 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.
+#
+
+import copy
+import zipfile
+
+import common
+import test_utils
+
+from non_ab_ota import NonAbOtaPropertyFiles, WriteFingerprintAssertion
+from test_utils import PropertyFilesTestCase
+
+
+class NonAbOtaPropertyFilesTest(PropertyFilesTestCase):
+  """Additional validity checks specialized for NonAbOtaPropertyFiles."""
+  def setUp(self):
+     common.OPTIONS.no_signing = False
+  def test_init(self):
+    property_files = NonAbOtaPropertyFiles()
+    self.assertEqual('ota-property-files', property_files.name)
+    self.assertEqual((), property_files.required)
+    self.assertEqual((), property_files.optional)
+
+  def test_Compute(self):
+    entries = ()
+    zip_file = self.construct_zip_package(entries)
+    property_files = NonAbOtaPropertyFiles()
+    with zipfile.ZipFile(zip_file) as zip_fp:
+      property_files_string = property_files.Compute(zip_fp)
+
+    tokens = self._parse_property_files_string(property_files_string)
+    self.assertEqual(1, len(tokens))
+    self._verify_entries(zip_file, tokens, entries)
+
+  def test_Finalize(self):
+    entries = [
+        'META-INF/com/android/metadata',
+    ]
+    zip_file = self.construct_zip_package(entries)
+    property_files = NonAbOtaPropertyFiles()
+    with zipfile.ZipFile(zip_file) as zip_fp:
+      raw_metadata = property_files.GetPropertyFilesString(
+          zip_fp, reserve_space=False)
+      property_files_string = property_files.Finalize(zip_fp, len(raw_metadata))
+    tokens = self._parse_property_files_string(property_files_string)
+
+    self.assertEqual(1, len(tokens))
+    # 'META-INF/com/android/metadata' will be key'd as 'metadata'.
+    entries[0] = 'metadata'
+    self._verify_entries(zip_file, tokens, entries)
+
+  def test_Verify(self):
+    entries = (
+        'META-INF/com/android/metadata',
+    )
+    zip_file = self.construct_zip_package(entries)
+    property_files = NonAbOtaPropertyFiles()
+    with zipfile.ZipFile(zip_file) as zip_fp:
+      raw_metadata = property_files.GetPropertyFilesString(
+          zip_fp, reserve_space=False)
+
+      property_files.Verify(zip_fp, raw_metadata)
+
+class NonAbOTATest(test_utils.ReleaseToolsTestCase):
+  TEST_TARGET_INFO_DICT = {
+      'build.prop': common.PartitionBuildProps.FromDictionary(
+          'system', {
+              'ro.product.device': 'product-device',
+              'ro.build.fingerprint': 'build-fingerprint-target',
+              'ro.build.version.incremental': 'build-version-incremental-target',
+              'ro.build.version.sdk': '27',
+              'ro.build.version.security_patch': '2017-12-01',
+              'ro.build.date.utc': '1500000000'}
+      )
+  }
+  TEST_INFO_DICT_USES_OEM_PROPS = {
+      'build.prop': common.PartitionBuildProps.FromDictionary(
+          'system', {
+              'ro.product.name': 'product-name',
+              'ro.build.thumbprint': 'build-thumbprint',
+              'ro.build.bar': 'build-bar'}
+      ),
+      'vendor.build.prop': common.PartitionBuildProps.FromDictionary(
+          'vendor', {
+               'ro.vendor.build.fingerprint': 'vendor-build-fingerprint'}
+      ),
+      'property1': 'value1',
+      'property2': 4096,
+      'oem_fingerprint_properties': 'ro.product.device ro.product.brand',
+  }
+  TEST_OEM_DICTS = [
+      {
+          'ro.product.brand': 'brand1',
+          'ro.product.device': 'device1',
+      },
+      {
+          'ro.product.brand': 'brand2',
+          'ro.product.device': 'device2',
+      },
+      {
+          'ro.product.brand': 'brand3',
+          'ro.product.device': 'device3',
+      },
+  ]
+  def test_WriteFingerprintAssertion_without_oem_props(self):
+    target_info = common.BuildInfo(self.TEST_TARGET_INFO_DICT, None)
+    source_info_dict = copy.deepcopy(self.TEST_TARGET_INFO_DICT)
+    source_info_dict['build.prop'].build_props['ro.build.fingerprint'] = (
+        'source-build-fingerprint')
+    source_info = common.BuildInfo(source_info_dict, None)
+
+    script_writer = test_utils.MockScriptWriter()
+    WriteFingerprintAssertion(script_writer, target_info, source_info)
+    self.assertEqual(
+        [('AssertSomeFingerprint', 'source-build-fingerprint',
+          'build-fingerprint-target')],
+        script_writer.lines)
+
+  def test_WriteFingerprintAssertion_with_source_oem_props(self):
+    target_info = common.BuildInfo(self.TEST_TARGET_INFO_DICT, None)
+    source_info = common.BuildInfo(self.TEST_INFO_DICT_USES_OEM_PROPS,
+                                   self.TEST_OEM_DICTS)
+
+    script_writer = test_utils.MockScriptWriter()
+    WriteFingerprintAssertion(script_writer, target_info, source_info)
+    self.assertEqual(
+        [('AssertFingerprintOrThumbprint', 'build-fingerprint-target',
+          'build-thumbprint')],
+        script_writer.lines)
+
+  def test_WriteFingerprintAssertion_with_target_oem_props(self):
+    target_info = common.BuildInfo(self.TEST_INFO_DICT_USES_OEM_PROPS,
+                                   self.TEST_OEM_DICTS)
+    source_info = common.BuildInfo(self.TEST_TARGET_INFO_DICT, None)
+
+    script_writer = test_utils.MockScriptWriter()
+    WriteFingerprintAssertion(script_writer, target_info, source_info)
+    self.assertEqual(
+        [('AssertFingerprintOrThumbprint', 'build-fingerprint-target',
+          'build-thumbprint')],
+        script_writer.lines)
+
+  def test_WriteFingerprintAssertion_with_both_oem_props(self):
+    target_info = common.BuildInfo(self.TEST_INFO_DICT_USES_OEM_PROPS,
+                                   self.TEST_OEM_DICTS)
+    source_info_dict = copy.deepcopy(self.TEST_INFO_DICT_USES_OEM_PROPS)
+    source_info_dict['build.prop'].build_props['ro.build.thumbprint'] = (
+        'source-build-thumbprint')
+    source_info = common.BuildInfo(source_info_dict, self.TEST_OEM_DICTS)
+
+    script_writer = test_utils.MockScriptWriter()
+    WriteFingerprintAssertion(script_writer, target_info, source_info)
+    self.assertEqual(
+        [('AssertSomeThumbprint', 'build-thumbprint',
+          'source-build-thumbprint')],
+        script_writer.lines)
diff --git a/tools/releasetools/test_ota_from_target_files.py b/tools/releasetools/test_ota_from_target_files.py
index 07b2e05..52aa487 100644
--- a/tools/releasetools/test_ota_from_target_files.py
+++ b/tools/releasetools/test_ota_from_target_files.py
@@ -21,14 +21,15 @@
 
 import common
 import test_utils
+from ota_utils import CalculateRuntimeDevicesAndFingerprints
 from ota_from_target_files import (
     _LoadOemDicts, AbOtaPropertyFiles, FinalizeMetadata,
     GetPackageMetadata, GetTargetFilesZipForSecondaryImages,
-    GetTargetFilesZipWithoutPostinstallConfig, NonAbOtaPropertyFiles,
+    GetTargetFilesZipWithoutPostinstallConfig,
     Payload, PayloadSigner, POSTINSTALL_CONFIG, PropertyFiles,
-    StreamingPropertyFiles, WriteFingerprintAssertion,
-    CalculateRuntimeDevicesAndFingerprints)
-
+    StreamingPropertyFiles)
+from non_ab_ota import NonAbOtaPropertyFiles
+from test_utils import PropertyFilesTestCase
 
 def construct_target_files(secondary=False):
   """Returns a target-files.zip file for generating OTA packages."""
@@ -149,20 +150,6 @@
       'oem_fingerprint_properties': 'ro.product.device ro.product.brand',
   }
 
-  TEST_OEM_DICTS = [
-      {
-          'ro.product.brand': 'brand1',
-          'ro.product.device': 'device1',
-      },
-      {
-          'ro.product.brand': 'brand2',
-          'ro.product.device': 'device2',
-      },
-      {
-          'ro.product.brand': 'brand3',
-          'ro.product.device': 'device3',
-      },
-  ]
 
   def setUp(self):
     self.testdata_dir = test_utils.get_testdata_dir()
@@ -529,59 +516,6 @@
     FinalizeMetadata(metadata, zip_file, output_file, needed_property_files)
     self.assertIn('ota-test-property-files', metadata)
 
-  def test_WriteFingerprintAssertion_without_oem_props(self):
-    target_info = common.BuildInfo(self.TEST_TARGET_INFO_DICT, None)
-    source_info_dict = copy.deepcopy(self.TEST_TARGET_INFO_DICT)
-    source_info_dict['build.prop'].build_props['ro.build.fingerprint'] = (
-        'source-build-fingerprint')
-    source_info = common.BuildInfo(source_info_dict, None)
-
-    script_writer = test_utils.MockScriptWriter()
-    WriteFingerprintAssertion(script_writer, target_info, source_info)
-    self.assertEqual(
-        [('AssertSomeFingerprint', 'source-build-fingerprint',
-          'build-fingerprint-target')],
-        script_writer.lines)
-
-  def test_WriteFingerprintAssertion_with_source_oem_props(self):
-    target_info = common.BuildInfo(self.TEST_TARGET_INFO_DICT, None)
-    source_info = common.BuildInfo(self.TEST_INFO_DICT_USES_OEM_PROPS,
-                                   self.TEST_OEM_DICTS)
-
-    script_writer = test_utils.MockScriptWriter()
-    WriteFingerprintAssertion(script_writer, target_info, source_info)
-    self.assertEqual(
-        [('AssertFingerprintOrThumbprint', 'build-fingerprint-target',
-          'build-thumbprint')],
-        script_writer.lines)
-
-  def test_WriteFingerprintAssertion_with_target_oem_props(self):
-    target_info = common.BuildInfo(self.TEST_INFO_DICT_USES_OEM_PROPS,
-                                   self.TEST_OEM_DICTS)
-    source_info = common.BuildInfo(self.TEST_TARGET_INFO_DICT, None)
-
-    script_writer = test_utils.MockScriptWriter()
-    WriteFingerprintAssertion(script_writer, target_info, source_info)
-    self.assertEqual(
-        [('AssertFingerprintOrThumbprint', 'build-fingerprint-target',
-          'build-thumbprint')],
-        script_writer.lines)
-
-  def test_WriteFingerprintAssertion_with_both_oem_props(self):
-    target_info = common.BuildInfo(self.TEST_INFO_DICT_USES_OEM_PROPS,
-                                   self.TEST_OEM_DICTS)
-    source_info_dict = copy.deepcopy(self.TEST_INFO_DICT_USES_OEM_PROPS)
-    source_info_dict['build.prop'].build_props['ro.build.thumbprint'] = (
-        'source-build-thumbprint')
-    source_info = common.BuildInfo(source_info_dict, self.TEST_OEM_DICTS)
-
-    script_writer = test_utils.MockScriptWriter()
-    WriteFingerprintAssertion(script_writer, target_info, source_info)
-    self.assertEqual(
-        [('AssertSomeThumbprint', 'build-thumbprint',
-          'source-build-thumbprint')],
-        script_writer.lines)
-
 
 class TestPropertyFiles(PropertyFiles):
   """A class that extends PropertyFiles for testing purpose."""
@@ -598,41 +532,8 @@
         'optional-entry2',
     )
 
+class PropertyFilesTest(PropertyFilesTestCase):
 
-class PropertyFilesTest(test_utils.ReleaseToolsTestCase):
-
-  def setUp(self):
-    common.OPTIONS.no_signing = False
-
-  @staticmethod
-  def construct_zip_package(entries):
-    zip_file = common.MakeTempFile(suffix='.zip')
-    with zipfile.ZipFile(zip_file, 'w') as zip_fp:
-      for entry in entries:
-        zip_fp.writestr(
-            entry,
-            entry.replace('.', '-').upper(),
-            zipfile.ZIP_STORED)
-    return zip_file
-
-  @staticmethod
-  def _parse_property_files_string(data):
-    result = {}
-    for token in data.split(','):
-      name, info = token.split(':', 1)
-      result[name] = info
-    return result
-
-  def _verify_entries(self, input_file, tokens, entries):
-    for entry in entries:
-      offset, size = map(int, tokens[entry].split(':'))
-      with open(input_file, 'rb') as input_fp:
-        input_fp.seek(offset)
-        if entry == 'metadata':
-          expected = b'META-INF/COM/ANDROID/METADATA'
-        else:
-          expected = entry.replace('.', '-').upper().encode()
-        self.assertEqual(expected, input_fp.read(size))
 
   @test_utils.SkipIfExternalToolsUnavailable()
   def test_Compute(self):
@@ -753,7 +654,7 @@
           AssertionError, property_files.Verify, zip_fp, raw_metadata + 'x')
 
 
-class StreamingPropertyFilesTest(PropertyFilesTest):
+class StreamingPropertyFilesTest(PropertyFilesTestCase):
   """Additional validity checks specialized for StreamingPropertyFiles."""
 
   def test_init(self):
@@ -834,7 +735,7 @@
           AssertionError, property_files.Verify, zip_fp, raw_metadata + 'x')
 
 
-class AbOtaPropertyFilesTest(PropertyFilesTest):
+class AbOtaPropertyFilesTest(PropertyFilesTestCase):
   """Additional validity checks specialized for AbOtaPropertyFiles."""
 
   # The size for payload and metadata signature size.
@@ -1002,56 +903,6 @@
       property_files.Verify(zip_fp, raw_metadata)
 
 
-class NonAbOtaPropertyFilesTest(PropertyFilesTest):
-  """Additional validity checks specialized for NonAbOtaPropertyFiles."""
-
-  def test_init(self):
-    property_files = NonAbOtaPropertyFiles()
-    self.assertEqual('ota-property-files', property_files.name)
-    self.assertEqual((), property_files.required)
-    self.assertEqual((), property_files.optional)
-
-  def test_Compute(self):
-    entries = ()
-    zip_file = self.construct_zip_package(entries)
-    property_files = NonAbOtaPropertyFiles()
-    with zipfile.ZipFile(zip_file) as zip_fp:
-      property_files_string = property_files.Compute(zip_fp)
-
-    tokens = self._parse_property_files_string(property_files_string)
-    self.assertEqual(1, len(tokens))
-    self._verify_entries(zip_file, tokens, entries)
-
-  def test_Finalize(self):
-    entries = [
-        'META-INF/com/android/metadata',
-    ]
-    zip_file = self.construct_zip_package(entries)
-    property_files = NonAbOtaPropertyFiles()
-    with zipfile.ZipFile(zip_file) as zip_fp:
-      raw_metadata = property_files.GetPropertyFilesString(
-          zip_fp, reserve_space=False)
-      property_files_string = property_files.Finalize(zip_fp, len(raw_metadata))
-    tokens = self._parse_property_files_string(property_files_string)
-
-    self.assertEqual(1, len(tokens))
-    # 'META-INF/com/android/metadata' will be key'd as 'metadata'.
-    entries[0] = 'metadata'
-    self._verify_entries(zip_file, tokens, entries)
-
-  def test_Verify(self):
-    entries = (
-        'META-INF/com/android/metadata',
-    )
-    zip_file = self.construct_zip_package(entries)
-    property_files = NonAbOtaPropertyFiles()
-    with zipfile.ZipFile(zip_file) as zip_fp:
-      raw_metadata = property_files.GetPropertyFilesString(
-          zip_fp, reserve_space=False)
-
-      property_files.Verify(zip_fp, raw_metadata)
-
-
 class PayloadSignerTest(test_utils.ReleaseToolsTestCase):
 
   SIGFILE = 'sigfile.bin'
diff --git a/tools/releasetools/test_utils.py b/tools/releasetools/test_utils.py
index e999757..65092d8 100755
--- a/tools/releasetools/test_utils.py
+++ b/tools/releasetools/test_utils.py
@@ -25,6 +25,7 @@
 import struct
 import sys
 import unittest
+import zipfile
 
 import common
 
@@ -192,6 +193,41 @@
   def tearDown(self):
     common.Cleanup()
 
+class PropertyFilesTestCase(ReleaseToolsTestCase):
+
+  @staticmethod
+  def construct_zip_package(entries):
+    zip_file = common.MakeTempFile(suffix='.zip')
+    with zipfile.ZipFile(zip_file, 'w') as zip_fp:
+      for entry in entries:
+        zip_fp.writestr(
+            entry,
+            entry.replace('.', '-').upper(),
+            zipfile.ZIP_STORED)
+    return zip_file
+
+  @staticmethod
+  def _parse_property_files_string(data):
+    result = {}
+    for token in data.split(','):
+      name, info = token.split(':', 1)
+      result[name] = info
+    return result
+
+  def setUp(self):
+    common.OPTIONS.no_signing = False
+
+  def _verify_entries(self, input_file, tokens, entries):
+    for entry in entries:
+      offset, size = map(int, tokens[entry].split(':'))
+      with open(input_file, 'rb') as input_fp:
+        input_fp.seek(offset)
+        if entry == 'metadata':
+          expected = b'META-INF/COM/ANDROID/METADATA'
+        else:
+          expected = entry.replace('.', '-').upper().encode()
+        self.assertEqual(expected, input_fp.read(size))
+
 
 if __name__ == '__main__':
   testsuite = unittest.TestLoader().discover(