diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 9bbdc51..3904a78 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -4001,3 +4001,26 @@
     # Magic for android sparse image format
     # https://source.android.com/devices/bootloader/images
     return fp.read(4) == b'\x3A\xFF\x26\xED'
+
+def ParseUpdateEngineConfig(path: str):
+  """Parse the update_engine config stored in file `path`
+  Args
+    path: Path to update_engine_config.txt file in target_files
+
+  Returns
+    A tuple of (major, minor) version number . E.g. (2, 8)
+  """
+  with open(path, "r") as fp:
+    # update_engine_config.txt is only supposed to contain two lines,
+    # PAYLOAD_MAJOR_VERSION and PAYLOAD_MINOR_VERSION. 1024 should be more than
+    # sufficient. If the length is more than that, something is wrong.
+    data = fp.read(1024)
+    major = re.search(r"PAYLOAD_MAJOR_VERSION=(\d+)", data)
+    if not major:
+      raise ValueError(
+          f"{path} is an invalid update_engine config, missing PAYLOAD_MAJOR_VERSION {data}")
+    minor = re.search(r"PAYLOAD_MINOR_VERSION=(\d+)", data)
+    if not minor:
+      raise ValueError(
+          f"{path} is an invalid update_engine config, missing PAYLOAD_MINOR_VERSION {data}")
+    return (int(major.group(1)), int(minor.group(1)))
\ No newline at end of file
diff --git a/tools/releasetools/merge/merge_meta.py b/tools/releasetools/merge/merge_meta.py
index 6fe3099..b61f039 100644
--- a/tools/releasetools/merge/merge_meta.py
+++ b/tools/releasetools/merge/merge_meta.py
@@ -29,6 +29,7 @@
 import merge_utils
 import sparse_img
 import verity_utils
+from ota_utils import ParseUpdateEngineConfig
 
 from common import ExternalError
 
@@ -52,28 +53,6 @@
 MODULE_KEY_PATTERN = re.compile(r'name="(.+)\.(apex|apk)"')
 
 
-def ParseUpdateEngineConfig(path: str):
-  """Parse the update_engine config stored in file `path`
-  Args
-    path: Path to update_engine_config.txt file in target_files
-
-  Returns
-    A tuple of (major, minor) version number . E.g. (2, 8)
-  """
-  with open(path, "r") as fp:
-    # update_engine_config.txt is only supposed to contain two lines,
-    # PAYLOAD_MAJOR_VERSION and PAYLOAD_MINOR_VERSION. 1024 should be more than
-    # sufficient. If the length is more than that, something is wrong.
-    data = fp.read(1024)
-    major = re.search(r"PAYLOAD_MAJOR_VERSION=(\d+)", data)
-    if not major:
-      raise ValueError(
-          f"{path} is an invalid update_engine config, missing PAYLOAD_MAJOR_VERSION {data}")
-    minor = re.search(r"PAYLOAD_MINOR_VERSION=(\d+)", data)
-    if not minor:
-      raise ValueError(
-          f"{path} is an invalid update_engine config, missing PAYLOAD_MINOR_VERSION {data}")
-    return (int(major.group(1)), int(minor.group(1)))
 
 
 def MergeUpdateEngineConfig(input_metadir1, input_metadir2, merged_meta_dir):
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 39e380e..2458244 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -906,7 +906,8 @@
     OPTIONS.enable_vabc_xor = False
 
   if OPTIONS.vabc_compression_param == "none":
-    logger.info("VABC Compression algorithm is set to 'none', disabling VABC xor")
+    logger.info(
+        "VABC Compression algorithm is set to 'none', disabling VABC xor")
     OPTIONS.enable_vabc_xor = False
   additional_args = []
 
@@ -922,7 +923,6 @@
   elif OPTIONS.partial:
     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)
@@ -938,7 +938,8 @@
   # Metadata to comply with Android OTA package format.
   metadata = GetPackageMetadata(target_info, source_info)
   # Generate payload.
-  payload = PayloadGenerator(wipe_user_data=OPTIONS.wipe_user_data)
+  payload = PayloadGenerator(
+      wipe_user_data=OPTIONS.wipe_user_data, minor_version=OPTIONS.force_minor_version, is_partial_update=OPTIONS.partial)
 
   partition_timestamps_flags = []
   # Enforce a max timestamp this payload can be applied on top of.
@@ -965,7 +966,7 @@
 
   additional_args += ["--security_patch_level", security_patch_level]
 
-  additional_args += ["--enable_zucchini",
+  additional_args += ["--enable_zucchini=" +
                       str(OPTIONS.enable_zucchini).lower()]
 
   if not ota_utils.IsLz4diffCompatible(source_file, target_file):
@@ -973,7 +974,7 @@
         "Source build doesn't support lz4diff, or source/target don't have compatible lz4diff versions. Disabling lz4diff.")
     OPTIONS.enable_lz4diff = False
 
-  additional_args += ["--enable_lz4diff",
+  additional_args += ["--enable_lz4diff=" +
                       str(OPTIONS.enable_lz4diff).lower()]
 
   if source_file and OPTIONS.enable_lz4diff:
@@ -989,20 +990,13 @@
     additional_args += ["--erofs_compression_param", erofs_compression_param]
 
   if OPTIONS.disable_vabc:
-    additional_args += ["--disable_vabc", "true"]
+    additional_args += ["--disable_vabc=true"]
   if OPTIONS.enable_vabc_xor:
-    additional_args += ["--enable_vabc_xor", "true"]
-  if OPTIONS.force_minor_version:
-    additional_args += ["--force_minor_version", OPTIONS.force_minor_version]
+    additional_args += ["--enable_vabc_xor=true"]
   if OPTIONS.compressor_types:
     additional_args += ["--compressor_types", OPTIONS.compressor_types]
   additional_args += ["--max_timestamp", max_timestamp]
 
-  if SupportsMainlineGkiUpdates(source_file):
-    logger.warning(
-        "Detected build with mainline GKI, include full boot image.")
-    additional_args.extend(["--full_boot", "true"])
-
   payload.Generate(
       target_file,
       source_file,
@@ -1363,7 +1357,8 @@
           "what(even if data wipe is done), so SPL downgrade on any "
           "release-keys build is not allowed.".format(target_spl, source_spl))
 
-    logger.info("SPL downgrade on %s", target_build_prop.GetProp("ro.build.tags"))
+    logger.info("SPL downgrade on %s",
+                target_build_prop.GetProp("ro.build.tags"))
     if is_spl_downgrade and not OPTIONS.spl_downgrade and not OPTIONS.downgrade:
       raise common.ExternalError(
           "Target security patch level {} is older than source SPL {} applying "
diff --git a/tools/releasetools/ota_utils.py b/tools/releasetools/ota_utils.py
index e2ce31d..c419537 100644
--- a/tools/releasetools/ota_utils.py
+++ b/tools/releasetools/ota_utils.py
@@ -25,7 +25,7 @@
 from common import (ZipDelete, OPTIONS, MakeTempFile,
                     ZipWriteStr, BuildInfo, LoadDictionaryFromFile,
                     SignFile, PARTITIONS_WITH_BUILD_PROP, PartitionBuildProps,
-                    GetRamdiskFormat)
+                    GetRamdiskFormat, ParseUpdateEngineConfig)
 from payload_signer import PayloadSigner
 
 
@@ -135,7 +135,8 @@
     logger.info(f"Signing disabled for output file {output_file}")
     shutil.copy(prelim_signing, output_file)
   else:
-    logger.info(f"Signing the output file {output_file} with key {package_key}")
+    logger.info(
+        f"Signing the output file {output_file} with key {package_key}")
     SignOutput(prelim_signing, output_file, package_key, pw)
 
   # Reopen the final signed zip to double check the streaming metadata.
@@ -721,6 +722,45 @@
   return sourceEntry and targetEntry and sourceEntry == targetEntry
 
 
+def ExtractTargetFiles(path: str):
+  if os.path.isdir(path):
+    logger.info("target files %s is already extracted", path)
+    return path
+  extracted_dir = common.MakeTempDir("target_files")
+  common.UnzipToDir(path, extracted_dir, UNZIP_PATTERN)
+  return extracted_dir
+
+
+def LocatePartitionPath(target_files_dir: str, partition: str, allow_empty):
+  path = os.path.join(target_files_dir, "RADIO", partition + ".img")
+  if os.path.exists(path):
+    return path
+  path = os.path.join(target_files_dir, "IMAGES", partition + ".img")
+  if os.path.exists(path):
+    return path
+  if allow_empty:
+    return ""
+  raise common.ExternalError(
+      "Partition {} not found in target files {}".format(partition, target_files_dir))
+
+
+def GetPartitionImages(target_files_dir: str, ab_partitions, allow_empty=True):
+  assert os.path.isdir(target_files_dir)
+  return ":".join([LocatePartitionPath(target_files_dir, partition, allow_empty) for partition in ab_partitions])
+
+
+def LocatePartitionMap(target_files_dir: str, partition: str):
+  path = os.path.join(target_files_dir, "RADIO", partition + ".map")
+  if os.path.exists(path):
+    return path
+  return ""
+
+
+def GetPartitionMaps(target_files_dir: str, ab_partitions):
+  assert os.path.isdir(target_files_dir)
+  return ":".join([LocatePartitionMap(target_files_dir, partition) for partition in ab_partitions])
+
+
 class PayloadGenerator(object):
   """Manages the creation and the signing of an A/B OTA Payload."""
 
@@ -729,7 +769,7 @@
   SECONDARY_PAYLOAD_BIN = 'secondary/payload.bin'
   SECONDARY_PAYLOAD_PROPERTIES_TXT = 'secondary/payload_properties.txt'
 
-  def __init__(self, secondary=False, wipe_user_data=False):
+  def __init__(self, secondary=False, wipe_user_data=False, minor_version=None, is_partial_update=False):
     """Initializes a Payload instance.
 
     Args:
@@ -739,6 +779,8 @@
     self.payload_properties = None
     self.secondary = secondary
     self.wipe_user_data = wipe_user_data
+    self.minor_version = minor_version
+    self.is_partial_update = is_partial_update
 
   def _Run(self, cmd):  # pylint: disable=no-self-use
     # Don't pipe (buffer) the output if verbose is set. Let
@@ -757,21 +799,53 @@
       source_file: The filename of the source build target-files zip; or None if
           generating a full OTA.
       additional_args: A list of additional args that should be passed to
-          brillo_update_payload script; or None.
+          delta_generator binary; or None.
     """
     if additional_args is None:
       additional_args = []
 
     payload_file = common.MakeTempFile(prefix="payload-", suffix=".bin")
-    cmd = ["brillo_update_payload", "generate",
-           "--payload", payload_file,
-           "--target_image", target_file]
+    target_dir = ExtractTargetFiles(target_file)
+    cmd = ["delta_generator",
+           "--out_file", payload_file]
+    with open(os.path.join(target_dir, "META", "ab_partitions.txt")) as fp:
+      ab_partitions = fp.read().strip().split("\n")
+    cmd.extend(["--partition_names", ":".join(ab_partitions)])
+    cmd.extend(
+        ["--new_partitions", GetPartitionImages(target_dir, ab_partitions, False)])
+    cmd.extend(
+        ["--new_mapfiles", GetPartitionMaps(target_dir, ab_partitions)])
     if source_file is not None:
-      cmd.extend(["--source_image", source_file])
+      source_dir = ExtractTargetFiles(source_file)
+      cmd.extend(
+          ["--old_partitions", GetPartitionImages(source_dir, ab_partitions, True)])
+      cmd.extend(
+          ["--old_mapfiles", GetPartitionMaps(source_dir, ab_partitions)])
+
       if OPTIONS.disable_fec_computation:
-        cmd.extend(["--disable_fec_computation", "true"])
+        cmd.extend(["--disable_fec_computation=true"])
       if OPTIONS.disable_verity_computation:
-        cmd.extend(["--disable_verity_computation", "true"])
+        cmd.extend(["--disable_verity_computation=true"])
+    postinstall_config = os.path.join(
+        target_dir, "META", "postinstall_config.txt")
+
+    if os.path.exists(postinstall_config):
+      cmd.extend(["--new_postinstall_config_file", postinstall_config])
+    dynamic_partition_info = os.path.join(
+        target_dir, "META", "dynamic_partitions_info.txt")
+
+    if os.path.exists(dynamic_partition_info):
+      cmd.extend(["--dynamic_partition_info_file", dynamic_partition_info])
+
+    major_version, minor_version = ParseUpdateEngineConfig(
+        os.path.join(target_dir, "META", "update_engine_config.txt"))
+    if self.minor_version:
+      minor_version = self.minor_version
+    cmd.extend(["--major_version", str(major_version)])
+    if source_file is not None or self.is_partial_update:
+      cmd.extend(["--minor_version", str(minor_version)])
+    if self.is_partial_update:
+      cmd.extend(["--is_partial_update=true"])
     cmd.extend(additional_args)
     self._Run(cmd)