diff --git a/METADATA b/METADATA
index 814cb00..44781a7 100644
--- a/METADATA
+++ b/METADATA
@@ -1,8 +1,8 @@
 third_party {
-  # would be NOTICE save for GPL in:
-  #   core/LINUX_KERNEL_COPYING
-  #   tools/droiddoc/templates-pdk/assets/jquery-1.6.2.min.js
-  #   tools/droiddoc/templates-pdk/assets/jquery-history.js
-  #   tools/droiddoc/templates-pdk/assets/jquery-resizable.min.js
+  license_note: "would be NOTICE save for GPL in:\n"
+  "   core/LINUX_KERNEL_COPYING\n"
+  "   tools/droiddoc/templates-pdk/assets/jquery-1.6.2.min.js\n"
+  "   tools/droiddoc/templates-pdk/assets/jquery-history.js\n"
+  "   tools/droiddoc/templates-pdk/assets/jquery-resizable.min.js"
   license_type: RESTRICTED
 }
diff --git a/core/android_soong_config_vars.mk b/core/android_soong_config_vars.mk
index 0befbfa..c6f4cb0 100644
--- a/core/android_soong_config_vars.mk
+++ b/core/android_soong_config_vars.mk
@@ -36,65 +36,79 @@
 $(call add_soong_config_var,ANDROID,BOARD_BUILD_SYSTEM_ROOT_IMAGE)
 $(call add_soong_config_var,ANDROID,PRODUCT_INSTALL_DEBUG_POLICY_TO_SYSTEM_EXT)
 
-ifneq (,$(filter sdk win_sdk sdk_addon,$(MAKECMDGOALS)))
-  # The artifacts in the SDK zip are OK to build with prebuilt stubs enabled,
-  # even if prebuilt apexes are not enabled, because the system images in the
-  # SDK stub are not currently used (and will be removed: b/205008975).
-  MODULE_BUILD_FROM_SOURCE ?= false
-else ifeq (,$(findstring com.google.android.conscrypt,$(PRODUCT_PACKAGES)))
+# Default behavior for the tree wrt building modules or using prebuilts. This
+# can always be overridden by setting the environment variable
+# MODULE_BUILD_FROM_SOURCE.
+BRANCH_DEFAULT_MODULE_BUILD_FROM_SOURCE := true
+
+ifneq (,$(MODULE_BUILD_FROM_SOURCE))
+  # Keep an explicit setting.
+else ifeq (,$(filter sdk win_sdk sdk_addon,$(MAKECMDGOALS))$(findstring com.google.android.conscrypt,$(PRODUCT_PACKAGES)))
   # Prebuilt module SDKs require prebuilt modules to work, and currently
   # prebuilt modules are only provided for com.google.android.xxx. If we can't
   # find one of them in PRODUCT_PACKAGES then assume com.android.xxx are in use,
   # and disable prebuilt SDKs. In particular this applies to AOSP builds.
+  #
+  # However, sdk/win_sdk/sdk_addon builds might not include com.google.android.xxx
+  # packages, so for those we respect the default behavior.
   MODULE_BUILD_FROM_SOURCE := true
+else ifeq (,$(filter-out modules_% mainline_modules_%,$(TARGET_PRODUCT)))
+  # Always build from source in unbundled builds using the module targets.
+  MODULE_BUILD_FROM_SOURCE := true
+else
+  MODULE_BUILD_FROM_SOURCE := $(BRANCH_DEFAULT_MODULE_BUILD_FROM_SOURCE)
+endif
+
+# TODO(b/220940864): Remove when build scripts have been changed to use
+# ART_MODULE_BUILD_FROM_SOURCE instead of SOONG_CONFIG_art_module_source_build
+ifneq (,$(SOONG_CONFIG_art_module_source_build))
+  ART_MODULE_BUILD_FROM_SOURCE := $(SOONG_CONFIG_art_module_source_build)
 endif
 
 # TODO(b/172480615): Remove when platform uses ART Module prebuilts by default.
-ifeq (,$(filter art_module,$(SOONG_CONFIG_NAMESPACES)))
-  $(call add_soong_config_namespace,art_module)
-  SOONG_CONFIG_art_module += source_build
-endif
-ifneq (,$(SOONG_CONFIG_art_module_source_build))
+ifneq (,$(ART_MODULE_BUILD_FROM_SOURCE))
   # Keep an explicit setting.
 else ifneq (,$(findstring .android.art,$(TARGET_BUILD_APPS)))
   # Build ART modules from source if they are listed in TARGET_BUILD_APPS.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 else ifeq (,$(filter-out modules_% mainline_modules_%,$(TARGET_PRODUCT)))
   # Always build from source for the module targets. This ought to be covered by
   # the TARGET_BUILD_APPS check above, but there are test builds that don't set it.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 else ifeq (true,$(MODULE_BUILD_FROM_SOURCE))
   # Build from source if other Mainline modules are.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 else ifneq (,$(filter true,$(NATIVE_COVERAGE) $(CLANG_COVERAGE)))
   # Always build ART APEXes from source in coverage builds since the prebuilts
   # aren't built with instrumentation.
   # TODO(b/172480617): Find another solution for this.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 else ifneq (,$(SANITIZE_TARGET)$(SANITIZE_HOST))
   # Prebuilts aren't built with sanitizers either.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
   MODULE_BUILD_FROM_SOURCE := true
 else ifeq (,$(filter x86 x86_64,$(HOST_CROSS_ARCH)))
   # We currently only provide prebuilts for x86 on host. This skips prebuilts in
   # cuttlefish builds for ARM servers.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 else ifneq (,$(filter dex2oatds dex2oats,$(PRODUCT_HOST_PACKAGES)))
   # Some products depend on host tools that aren't available as prebuilts.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 else ifeq (,$(findstring com.google.android.art,$(PRODUCT_PACKAGES)))
   # TODO(b/192006406): There is currently no good way to control which prebuilt
   # APEX (com.google.android.art or com.android.art) gets picked for deapexing
   # to provide dex jars for hiddenapi and dexpreopting. Instead the AOSP APEX is
   # completely disabled, and we build from source for AOSP products.
-  SOONG_CONFIG_art_module_source_build := true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 else
   # This sets the default for building ART APEXes from source rather than
   # prebuilts (in packages/modules/ArtPrebuilt and prebuilt/module_sdk/art) in
   # all other platform builds.
-  SOONG_CONFIG_art_module_source_build ?= true
+  ART_MODULE_BUILD_FROM_SOURCE := true
 endif
 
+$(call soong_config_set,art_module,source_build,$(ART_MODULE_BUILD_FROM_SOURCE))
+
 # Apex build mode variables
 ifdef APEX_BUILD_FOR_PRE_S_DEVICES
 $(call add_soong_config_var_value,ANDROID,library_linking_strategy,prefer_static)
diff --git a/core/product.mk b/core/product.mk
index 43724a8..60b2dc9 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -14,98 +14,6 @@
 # limitations under the License.
 #
 
-#
-# Functions for including AndroidProducts.mk files
-# PRODUCT_MAKEFILES is set up in AndroidProducts.mks.
-# Format of PRODUCT_MAKEFILES:
-# <product_name>:<path_to_the_product_makefile>
-# If the <product_name> is the same as the base file name (without dir
-# and the .mk suffix) of the product makefile, "<product_name>:" can be
-# omitted.
-
-#
-# Returns the list of all AndroidProducts.mk files.
-# $(call ) isn't necessary.
-#
-define _find-android-products-files
-$(file <$(OUT_DIR)/.module_paths/AndroidProducts.mk.list) \
-  $(SRC_TARGET_DIR)/product/AndroidProducts.mk
-endef
-
-#
-# For entries returned by get-product-makefiles, decode an entry to a short
-# product name. These either may be in the form of <name>:path/to/file.mk or
-# path/to/<name>.mk
-# $(1): The entry to decode
-#
-# Returns two words:
-#   <name> <file>
-#
-define _decode-product-name
-$(strip \
-  $(eval _cpm_words := $(subst :,$(space),$(1))) \
-  $(if $(word 2,$(_cpm_words)), \
-    $(wordlist 1,2,$(_cpm_words)), \
-    $(basename $(notdir $(1))) $(1)))
-endef
-
-#
-# Validates the new common lunch choices -- ensures that they're in an
-# appropriate form, and are paired with definitions of their products.
-# $(1): The new list of COMMON_LUNCH_CHOICES
-# $(2): The new list of PRODUCT_MAKEFILES
-#
-define _validate-common-lunch-choices
-$(strip $(foreach choice,$(1),\
-  $(eval _parts := $(subst -,$(space),$(choice))) \
-  $(if $(call math_lt,$(words $(_parts)),2), \
-    $(error $(LOCAL_DIR): $(choice): Invalid lunch choice)) \
-  $(if $(call math_gt_or_eq,$(words $(_parts)),4), \
-    $(error $(LOCAL_DIR): $(choice): Invalid lunch choice)) \
-  $(if $(filter-out eng userdebug user,$(word 2,$(_parts))), \
-    $(error $(LOCAL_DIR): $(choice): Invalid variant: $(word 2,$(_parts)))) \
-  $(if $(filter-out $(foreach p,$(2),$(call _decode-product-name,$(p))),$(word 1,$(_parts))), \
-    $(error $(LOCAL_DIR): $(word 1,$(_parts)): Product not defined in this file)) \
-  ))
-endef
-
-#
-# Returns the sorted concatenation of PRODUCT_MAKEFILES
-# variables set in the given AndroidProducts.mk files.
-# $(1): the list of AndroidProducts.mk files.
-#
-# As a side-effect, COMMON_LUNCH_CHOICES will be set to a
-# union of all of the COMMON_LUNCH_CHOICES definitions within
-# each AndroidProducts.mk file.
-#
-define get-product-makefiles
-$(sort \
-  $(eval _COMMON_LUNCH_CHOICES :=) \
-  $(foreach f,$(1), \
-    $(eval PRODUCT_MAKEFILES :=) \
-    $(eval COMMON_LUNCH_CHOICES :=) \
-    $(eval LOCAL_DIR := $(patsubst %/,%,$(dir $(f)))) \
-    $(eval include $(f)) \
-    $(call _validate-common-lunch-choices,$(COMMON_LUNCH_CHOICES),$(PRODUCT_MAKEFILES)) \
-    $(eval _COMMON_LUNCH_CHOICES += $(COMMON_LUNCH_CHOICES)) \
-    $(PRODUCT_MAKEFILES) \
-   ) \
-  $(eval PRODUCT_MAKEFILES :=) \
-  $(eval LOCAL_DIR :=) \
-  $(eval COMMON_LUNCH_CHOICES := $(sort $(_COMMON_LUNCH_CHOICES))) \
-  $(eval _COMMON_LUNCH_CHOICES :=) \
- )
-endef
-
-#
-# Returns the sorted concatenation of all PRODUCT_MAKEFILES
-# variables set in all AndroidProducts.mk files.
-# $(call ) isn't necessary.
-#
-define get-all-product-makefiles
-$(call get-product-makefiles,$(_find-android-products-files))
-endef
-
 # Variables that are meant to hold only a single value.
 # - The value set in the current makefile takes precedence over inherited values
 # - If multiple inherited makefiles set the var, the first-inherited value wins
diff --git a/core/product_config.mk b/core/product_config.mk
index 1deb39b..be4aded 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -146,32 +146,73 @@
 include $(BUILD_SYSTEM)/product.mk
 include $(BUILD_SYSTEM)/device.mk
 
-# Read in all of the product definitions specified by the AndroidProducts.mk
-# files in the tree.
-all_product_configs := $(get-all-product-makefiles)
+# Read all product definitions.
+#
+# Products are defined in AndroidProducts.mk files:
+android_products_makefiles := $(file <$(OUT_DIR)/.module_paths/AndroidProducts.mk.list) \
+  $(SRC_TARGET_DIR)/product/AndroidProducts.mk
 
-all_named_products :=
+# An AndroidProduct.mk file sets the following variables:
+#   PRODUCT_MAKEFILES specifies product makefiles. Each item in this list
+#     is either a <product>:path/to/file.mk, or just path/to/<product.mk>
+#   COMMON_LUNCH_CHOICES specifies <product>-<variant> values to be shown
+#     in the `lunch` menu
+#   STARLARK_OPT_IN_PRODUCTS specifies products to use Starlark-based
+#     product configuration by default
 
-# Find the product config makefile for the current product.
-# all_product_configs consists items like:
-# <product_name>:<path_to_the_product_makefile>
-# or just <path_to_the_product_makefile> in case the product name is the
-# same as the base filename of the product config makefile.
-current_product_makefile :=
-all_product_makefiles :=
-$(foreach f, $(all_product_configs),\
-    $(eval _cpm_words := $(call _decode-product-name,$(f)))\
-    $(eval _cpm_word1 := $(word 1,$(_cpm_words)))\
-    $(eval _cpm_word2 := $(word 2,$(_cpm_words)))\
-    $(eval all_product_makefiles += $(_cpm_word2))\
-    $(eval all_named_products += $(_cpm_word1))\
-    $(if $(filter $(TARGET_PRODUCT),$(_cpm_word1)),\
-        $(eval current_product_makefile += $(_cpm_word2)),))
-_cpm_words :=
-_cpm_word1 :=
-_cpm_word2 :=
-current_product_makefile := $(strip $(current_product_makefile))
-all_product_makefiles := $(strip $(all_product_makefiles))
+# Builds a list of first/second elements of each pair:
+#   $(call _first,a:A b:B,:) returns 'a b'
+#   $(call _second,a-A b-B,-) returns 'A B'
+_first=$(filter-out $(2)%,$(subst $(2),$(space)$(2),$(1)))
+_second=$(filter-out %$(2),$(subst $(2),$(2)$(space),$(1)))
+
+# Returns <product>:<path> pair from a PRODUCT_MAKEFILE item.
+# If an item is <product>:path/to/file.mk, return it as is,
+# otherwise assume that an item is path/to/<product>.mk and
+# return <product>:path/to/<product>.mk
+_product-spec=$(strip $(if $(findstring :,$(1)),$(1),$(basename $(notdir $(1))):$(1)))
+
+# Reads given AndroidProduct.mk file and sets the following variables:
+#  ap_product_paths -- the list of <product>:<path> pairs
+#  ap_common_lunch_choices -- the list of <product>-<build variant> items
+#  ap_products_using_starlark_config -- the list of products using starlark config
+# In addition, validates COMMON_LUNCH_CHOICES and STARLARK_OPT_IN_PRODUCTS values
+define _read-ap-file
+  $(eval PRODUCT_MAKEFILES :=) \
+  $(eval COMMON_LUNCH_CHOICES :=) \
+  $(eval STARLARK_OPT_IN_PRODUCTS := ) \
+  $(eval ap_product_paths :=) \
+  $(eval LOCAL_DIR := $(patsubst %/,%,$(dir $(f)))) \
+  $(eval include $(f)) \
+  $(foreach p, $(PRODUCT_MAKEFILES),$(eval ap_product_paths += $(call _product-spec,$(p)))) \
+  $(eval ap_common_lunch_choices  := $(COMMON_LUNCH_CHOICES)) \
+  $(eval ap_products_using_starlark_config := $(STARLARK_OPT_IN_PRODUCTS)) \
+  $(eval _products := $(call _first,$(ap_product_paths),:)) \
+  $(eval _bad := $(filter-out $(_products),$(call _first,$(ap_common_lunch_choices),-))) \
+  $(if $(_bad),$(error COMMON_LUNCH_CHOICES contains products(s) not defined in this file: $(_bad))) \
+  $(eval _bad := $(filter-out %-eng %-userdebug %-user,$(ap_common_lunch_choices))) \
+  $(if $(_bad),$(error invalid variant in COMMON_LUNCH_CHOICES: $(_bad)))
+  $(eval _bad := $(filter-out $(_products),$(ap_products_using_starlark_config))) \
+  $(if $(_bad),$(error STARLARK_OPT_IN_PRODUCTS contains product(s) not defined in this file: $(_bad)))
+endef
+
+# Build cumulative lists of all product specs/lunch choices/Starlark-based products.
+product_paths :=
+common_lunch_choices :=
+products_using_starlark_config :=
+$(foreach f,$(android_products_makefiles), \
+    $(call _read-ap-file,$(f)) \
+    $(eval product_paths += $(ap_product_paths)) \
+    $(eval common_lunch_choices += $(ap_common_lunch_choices)) \
+    $(eval products_using_starlark_config += $(ap_products_using_starlark_config)) \
+)
+
+# Dedup, extract product names, etc.
+product_paths :=$(sort $(product_paths))
+all_named_products := $(call _first,$(product_paths),:)
+all_product_makefiles := $(call _second,$(product_paths),:)
+current_product_makefile := $(call _second,$(filter $(TARGET_PRODUCT):%,$(product_paths)),:)
+COMMON_LUNCH_CHOICES := $(sort $(common_lunch_choices))
 
 load_all_product_makefiles :=
 ifneq (,$(filter product-graph, $(MAKECMDGOALS)))
@@ -195,11 +236,10 @@
 $(call import-products, $(all_product_makefiles))
 else
 # Import just the current product.
-ifndef current_product_makefile
-$(error Can not locate config makefile for product "$(TARGET_PRODUCT)")
-endif
-ifneq (1,$(words $(current_product_makefile)))
-$(error Product "$(TARGET_PRODUCT)" ambiguous: matches $(current_product_makefile))
+$(if $(current_product_makefile),,$(error Can not locate config makefile for product "$(TARGET_PRODUCT)"))
+ifneq (,$(filter $(TARGET_PRODUCT),$(products_using_starlark_config)))
+  RBC_PRODUCT_CONFIG := true
+  RBC_BOARD_CONFIG := true
 endif
 
 ifndef RBC_PRODUCT_CONFIG
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 93e7042..43c39fb 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -241,6 +241,9 @@
   --spl_downgrade
       Force generate an SPL downgrade OTA. Only needed if target build has an
       older SPL.
+
+  --vabc_compression_param
+      Compression algorithm to be used for VABC. Available options: gz, brotli, none
 """
 
 from __future__ import print_function
@@ -312,6 +315,7 @@
 OPTIONS.compressor_types = None
 OPTIONS.enable_zucchini = True
 OPTIONS.enable_lz4diff = False
+OPTIONS.vabc_compression_param = None
 
 POSTINSTALL_CONFIG = 'META/postinstall_config.txt'
 DYNAMIC_PARTITION_INFO = 'META/dynamic_partitions_info.txt'
@@ -651,6 +655,24 @@
     return (payload_offset, metadata_total)
 
 
+def ModifyVABCCompressionParam(content, algo):
+  """ Update update VABC Compression Param in dynamic_partitions_info.txt
+  Args:
+    content: The string content of dynamic_partitions_info.txt
+    algo: The compression algorithm should be used for VABC. See
+          https://cs.android.com/android/platform/superproject/+/master:system/core/fs_mgr/libsnapshot/cow_writer.cpp;l=127;bpv=1;bpt=1?q=CowWriter::ParseOptions&sq=
+  Returns:
+    Updated content of dynamic_partitions_info.txt , with custom compression algo
+  """
+  output_list = []
+  for line in content.splitlines():
+    if line.startswith("virtual_ab_compression_method="):
+      continue
+    output_list.append(line)
+  output_list.append("virtual_ab_compression_method="+algo)
+  return "\n".join(output_list)
+
+
 def UpdatesInfoForSpecialUpdates(content, partitions_filter,
                                  delete_keys=None):
   """ Updates info file for secondary payload generation, partial update, etc.
@@ -805,6 +827,27 @@
     return common.LoadInfoDict(zfp)
 
 
+def GetTargetFilesZipForCustomVABCCompression(input_file, vabc_compression_param):
+  """Returns a target-files.zip with a custom VABC compression param.
+  Args:
+    input_file: The input target-files.zip path
+    vabc_compression_param: Custom Virtual AB Compression algorithm
+
+  Returns:
+    The path to modified target-files.zip
+  """
+  target_file = common.MakeTempFile(prefix="targetfiles-", suffix=".zip")
+  shutil.copyfile(input_file, target_file)
+  common.ZipDelete(target_file, DYNAMIC_PARTITION_INFO)
+  with zipfile.ZipFile(input_file, 'r', allowZip64=True) as zfp:
+    dynamic_partition_info = zfp.read(DYNAMIC_PARTITION_INFO).decode()
+    dynamic_partition_info = ModifyVABCCompressionParam(
+        dynamic_partition_info, vabc_compression_param)
+    with zipfile.ZipFile(target_file, "a", allowZip64=True) as output_zip:
+      output_zip.writestr(DYNAMIC_PARTITION_INFO, dynamic_partition_info)
+  return target_file
+
+
 def GetTargetFilesZipForPartialUpdates(input_file, ab_partitions):
   """Returns a target-files.zip for partial ota update package generation.
 
@@ -879,6 +922,9 @@
       content = input_zip.read(info_file).decode()
       modified_info = UpdatesInfoForSpecialUpdates(
           content, lambda p: p in ab_partitions)
+      if OPTIONS.vabc_compression_param and info_file == DYNAMIC_PARTITION_INFO:
+        modified_info = ModifyVABCCompressionParam(
+            modified_info, OPTIONS.vabc_compression_param)
       common.ZipWriteStr(partial_target_zip, info_file, modified_info)
 
     # TODO(xunchang) handle META/postinstall_config.txt'
@@ -1114,7 +1160,7 @@
   # Source build's update_engine must be able to write XOR ops, and target
   # build's snapuserd must be able to interpret XOR ops.
   if not target_info.is_vabc_xor or OPTIONS.disable_vabc or \
-      (source_info is not None and not source_info.is_vabc_xor):
+          (source_info is not None and not source_info.is_vabc_xor):
     logger.info("VABC XOR Not supported, disabling")
     OPTIONS.enable_vabc_xor = False
   additional_args = []
@@ -1132,6 +1178,9 @@
     target_file = GetTargetFilesZipForPartialUpdates(target_file,
                                                      OPTIONS.partial)
     additional_args += ["--is_partial_update", "true"]
+  elif OPTIONS.vabc_compression_param:
+    target_file = GetTargetFilesZipForCustomVABCCompression(
+        target_file, OPTIONS.vabc_compression_param)
   elif OPTIONS.skip_postinstall:
     target_file = GetTargetFilesZipWithoutPostinstallConfig(target_file)
   # Target_file may have been modified, reparse ab_partitions
@@ -1166,7 +1215,7 @@
                       str(OPTIONS.enable_zucchini).lower()]
 
   if not ota_utils.IsLz4diffCompatible(source_file, target_file):
-    logger.warn(
+    logger.warning(
         "Source build doesn't support lz4diff, or source/target don't have compatible lz4diff versions. Disabling lz4diff.")
     OPTIONS.enable_lz4diff = False
 
@@ -1377,6 +1426,8 @@
     elif o == "--enable_lz4diff":
       assert a.lower() in ["true", "false"]
       OPTIONS.enable_lz4diff = a.lower() != "false"
+    elif o == "--vabc_compression_param":
+      OPTIONS.vabc_compression_param = a.lower()
     else:
       return False
     return True
@@ -1426,6 +1477,7 @@
                                  "compressor_types=",
                                  "enable_zucchin=",
                                  "enable_lz4diff=",
+                                 "vabc_compression_param=",
                              ], extra_option_handler=option_handler)
 
   if len(args) != 2:
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 054315f..a24fbdd 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -1321,8 +1321,12 @@
     os.remove(os.path.join(vendor_tempdir, "META/pack_radioimages.txt"))
 
   # Build vendor images using vendor otatools.
-  vendor_otatools_dir = common.MakeTempDir(prefix="vendor_otatools_")
-  common.UnzipToDir(OPTIONS.vendor_otatools, vendor_otatools_dir)
+  # Accept either a zip file or extracted directory.
+  if os.path.isfile(OPTIONS.vendor_otatools):
+    vendor_otatools_dir = common.MakeTempDir(prefix="vendor_otatools_")
+    common.UnzipToDir(OPTIONS.vendor_otatools, vendor_otatools_dir)
+  else:
+    vendor_otatools_dir = OPTIONS.vendor_otatools
   cmd = [
       os.path.join(vendor_otatools_dir, "bin", "add_img_to_target_files"),
       "--is_signing",