diff --git a/tools/releasetools/merge_ota.py b/tools/releasetools/merge_ota.py
new file mode 100644
index 0000000..7d3d3a3
--- /dev/null
+++ b/tools/releasetools/merge_ota.py
@@ -0,0 +1,262 @@
+# Copyright (C) 2022 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 argparse
+import logging
+import struct
+import sys
+import update_payload
+import tempfile
+import zipfile
+import os
+import care_map_pb2
+
+import common
+from typing import BinaryIO, List
+from update_metadata_pb2 import DeltaArchiveManifest, DynamicPartitionMetadata, DynamicPartitionGroup
+from ota_metadata_pb2 import OtaMetadata
+from update_payload import Payload
+
+from payload_signer import PayloadSigner
+from ota_utils import PayloadGenerator, METADATA_PROTO_NAME, FinalizeMetadata
+
+logger = logging.getLogger(__name__)
+
+CARE_MAP_ENTRY = "care_map.pb"
+
+
+def WriteDataBlob(payload: Payload, outfp: BinaryIO, read_size=1024*64):
+  for i in range(0, payload.total_data_length, read_size):
+    blob = payload.ReadDataBlob(
+        i, min(i+read_size, payload.total_data_length)-i)
+    outfp.write(blob)
+
+
+def ConcatBlobs(payloads: List[Payload], outfp: BinaryIO):
+  for payload in payloads:
+    WriteDataBlob(payload, outfp)
+
+
+def TotalDataLength(partitions):
+  for partition in reversed(partitions):
+    for op in reversed(partition.operations):
+      if op.data_length > 0:
+        return op.data_offset + op.data_length
+  return 0
+
+
+def ExtendPartitionUpdates(partitions, new_partitions):
+  prefix_blob_length = TotalDataLength(partitions)
+  partitions.extend(new_partitions)
+  for part in partitions[-len(new_partitions):]:
+    for op in part.operations:
+      if op.HasField("data_length") and op.data_length != 0:
+        op.data_offset += prefix_blob_length
+
+
+class DuplicatePartitionError(ValueError):
+  pass
+
+
+def MergeDynamicPartitionGroups(groups: List[DynamicPartitionGroup], new_groups: List[DynamicPartitionGroup]):
+  new_groups = {new_group.name: new_group for new_group in new_groups}
+  for group in groups:
+    if group.name not in new_groups:
+      continue
+    new_group = new_groups[group.name]
+    common_partitions = set(group.partition_names).intersection(
+        set(new_group.partition_names))
+    if len(common_partitions) != 0:
+      raise DuplicatePartitionError(
+          f"Old group and new group should not have any intersections, {group.partition_names}, {new_group.partition_names}, common partitions: {common_partitions}")
+    group.partition_names.extend(new_group.partition_names)
+    group.size = max(new_group.size, group.size)
+    del new_groups[group.name]
+  for new_group in new_groups.values():
+    groups.append(new_group)
+
+
+def MergeDynamicPartitionMetadata(metadata: DynamicPartitionMetadata, new_metadata: DynamicPartitionMetadata):
+  MergeDynamicPartitionGroups(metadata.groups, new_metadata.groups)
+  metadata.snapshot_enabled &= new_metadata.snapshot_enabled
+  metadata.vabc_enabled &= new_metadata.vabc_enabled
+  assert metadata.vabc_compression_param == new_metadata.vabc_compression_param, f"{metadata.vabc_compression_param} vs. {new_metadata.vabc_compression_param}"
+  metadata.cow_version = max(metadata.cow_version, new_metadata.cow_version)
+
+
+def MergeManifests(payloads: List[Payload]) -> DeltaArchiveManifest:
+  if len(payloads) == 0:
+    return None
+  if len(payloads) == 1:
+    return payloads[0].manifest
+
+  output_manifest = DeltaArchiveManifest()
+  output_manifest.block_size = payloads[0].manifest.block_size
+  output_manifest.partial_update = True
+  output_manifest.dynamic_partition_metadata.snapshot_enabled = payloads[
+      0].manifest.dynamic_partition_metadata.snapshot_enabled
+  output_manifest.dynamic_partition_metadata.vabc_enabled = payloads[
+      0].manifest.dynamic_partition_metadata.vabc_enabled
+  output_manifest.dynamic_partition_metadata.vabc_compression_param = payloads[
+      0].manifest.dynamic_partition_metadata.vabc_compression_param
+  apex_info = {}
+  for payload in payloads:
+    manifest = payload.manifest
+    assert manifest.block_size == output_manifest.block_size
+    output_manifest.minor_version = max(
+        output_manifest.minor_version, manifest.minor_version)
+    output_manifest.max_timestamp = max(
+        output_manifest.max_timestamp, manifest.max_timestamp)
+    output_manifest.apex_info.extend(manifest.apex_info)
+    for apex in manifest.apex_info:
+      apex_info[apex.package_name] = apex
+    ExtendPartitionUpdates(output_manifest.partitions, manifest.partitions)
+    try:
+      MergeDynamicPartitionMetadata(
+        output_manifest.dynamic_partition_metadata, manifest.dynamic_partition_metadata)
+    except DuplicatePartitionError:
+      logger.error(
+          "OTA %s has duplicate partition with some of the previous OTAs", payload.name)
+      raise
+
+  for apex_name in sorted(apex_info.keys()):
+    output_manifest.apex_info.extend(apex_info[apex_name])
+
+  return output_manifest
+
+
+def MergePayloads(payloads: List[Payload]):
+  with tempfile.NamedTemporaryFile(prefix="payload_blob") as tmpfile:
+    ConcatBlobs(payloads, tmpfile)
+
+
+def MergeCareMap(paths: List[str]):
+  care_map = care_map_pb2.CareMap()
+  for path in paths:
+    with zipfile.ZipFile(path, "r", allowZip64=True) as zfp:
+      if CARE_MAP_ENTRY in zfp.namelist():
+        care_map_bytes = zfp.read(CARE_MAP_ENTRY)
+        partial_care_map = care_map_pb2.CareMap()
+        partial_care_map.ParseFromString(care_map_bytes)
+        care_map.partitions.extend(partial_care_map.partitions)
+  if len(care_map.partitions) == 0:
+    return b""
+  return care_map.SerializeToString()
+
+
+def WriteHeaderAndManifest(manifest: DeltaArchiveManifest, fp: BinaryIO):
+  __MAGIC = b"CrAU"
+  __MAJOR_VERSION = 2
+  manifest_bytes = manifest.SerializeToString()
+  fp.write(struct.pack(f">4sQQL", __MAGIC,
+           __MAJOR_VERSION, len(manifest_bytes), 0))
+  fp.write(manifest_bytes)
+
+
+def AddOtaMetadata(input_ota, metadata_ota, output_ota, package_key, pw):
+  with zipfile.ZipFile(metadata_ota, 'r') as zfp:
+    metadata = OtaMetadata()
+    metadata.ParseFromString(zfp.read(METADATA_PROTO_NAME))
+    FinalizeMetadata(metadata, input_ota, output_ota,
+                     package_key=package_key, pw=pw)
+    return output_ota
+
+
+def CheckOutput(output_ota):
+  payload = update_payload.Payload(output_ota)
+  payload.CheckOpDataHash()
+
+
+def CheckDuplicatePartitions(payloads: List[Payload]):
+  partition_to_ota = {}
+  for payload in payloads:
+    for group in payload.manifest.dynamic_partition_metadata.groups:
+      for part in group.partition_names:
+        if part in partition_to_ota:
+          raise DuplicatePartitionError(
+              f"OTA {partition_to_ota[part].name} and {payload.name} have duplicating partition {part}")
+        partition_to_ota[part] = payload
+
+def main(argv):
+  parser = argparse.ArgumentParser(description='Merge multiple partial OTAs')
+  parser.add_argument('packages', type=str, nargs='+',
+                      help='Paths to OTA packages to merge')
+  parser.add_argument('--package_key', type=str,
+                      help='Paths to private key for signing payload')
+  parser.add_argument('--search_path', type=str,
+                      help='Search path for framework/signapk.jar')
+  parser.add_argument('--output', type=str,
+                      help='Paths to output merged ota', required=True)
+  parser.add_argument('--metadata_ota', type=str,
+                      help='Output zip will use build metadata from this OTA package, if unspecified, use the last OTA package in merge list')
+  parser.add_argument('--private_key_suffix', type=str,
+                      help='Suffix to be appended to package_key path', default=".pk8")
+  parser.add_argument('-v', action="store_true", help="Enable verbose logging", dest="verbose")
+  args = parser.parse_args(argv[1:])
+  file_paths = args.packages
+
+  common.OPTIONS.verbose = args.verbose
+  if args.verbose:
+    logger.setLevel(logging.INFO)
+
+  logger.info(args)
+  if args.search_path:
+    common.OPTIONS.search_path = args.search_path
+
+  metadata_ota = args.packages[-1]
+  if args.metadata_ota is not None:
+    metadata_ota = args.metadata_ota
+    assert os.path.exists(metadata_ota)
+
+  payloads = [Payload(path) for path in file_paths]
+
+  CheckDuplicatePartitions(payloads)
+
+  merged_manifest = MergeManifests(payloads)
+
+  with tempfile.NamedTemporaryFile() as unsigned_payload:
+    WriteHeaderAndManifest(merged_manifest, unsigned_payload)
+    ConcatBlobs(payloads, unsigned_payload)
+    unsigned_payload.flush()
+
+    generator = PayloadGenerator()
+    generator.payload_file = unsigned_payload.name
+    logger.info("Payload size: %d", os.path.getsize(generator.payload_file))
+
+    if args.package_key:
+      logger.info("Signing payload...")
+      signer = PayloadSigner(args.package_key, args.private_key_suffix)
+      generator.payload_file = unsigned_payload.name
+      generator.Sign(signer)
+
+    logger.info("Payload size: %d", os.path.getsize(generator.payload_file))
+
+    logger.info("Writing to %s", args.output)
+    key_passwords = common.GetKeyPasswords([args.package_key])
+    with tempfile.NamedTemporaryFile(prefix="signed_ota", suffix=".zip") as signed_ota:
+      with zipfile.ZipFile(signed_ota, "w") as zfp:
+        generator.WriteToZip(zfp)
+        care_map_bytes = MergeCareMap(args.packages)
+        if care_map_bytes:
+          zfp.writestr(CARE_MAP_ENTRY, care_map_bytes)
+      AddOtaMetadata(signed_ota.name, metadata_ota,
+                     args.output, args.package_key, key_passwords[args.package_key])
+  return 0
+
+
+
+
+if __name__ == '__main__':
+  logging.basicConfig()
+  sys.exit(main(sys.argv))