diff --git a/scripts/simulate_ota.py b/scripts/simulate_ota.py
new file mode 100644
index 0000000..6349979
--- /dev/null
+++ b/scripts/simulate_ota.py
@@ -0,0 +1,147 @@
+#
+# 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.
+#
+
+"""Tools for running host side simulation of an OTA update."""
+
+
+from __future__ import print_function
+
+import argparse
+import filecmp
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+import zipfile
+
+import update_payload
+
+
+def extract_file(zip_file_path, entry_name, target_file_path):
+  """Extract a file from zip archive into |target_file_path|"""
+  with open(target_file_path, 'wb') as out_fp:
+    if isinstance(zip_file_path, zipfile.ZipFile):
+      with zip_file_path.open(entry_name) as fp:
+        shutil.copyfileobj(fp, out_fp)
+    elif os.path.isdir(zip_file_path):
+      with open(os.path.join(zip_file_path, entry_name), "rb") as fp:
+        shutil.copyfileobj(fp, out_fp)
+
+def is_sparse_image(filepath):
+  with open(filepath, 'rb') as fp:
+    # Magic for android sparse image format
+    # https://source.android.com/devices/bootloader/images
+    return fp.read(4) == b'\x3A\xFF\x26\xED'
+
+def extract_img(zip_archive, img_name, output_path):
+  entry_name = "IMAGES/" + img_name + ".img"
+  extract_file(zip_archive, entry_name, output_path)
+  if is_sparse_image(output_path):
+    raw_img_path = output_path + ".raw"
+    subprocess.check_output(["simg2img", output_path, raw_img_path])
+    os.rename(raw_img_path, output_path)
+
+def run_ota(source, target, payload_path, tempdir):
+  """Run an OTA on host side"""
+  payload = update_payload.Payload(payload_path)
+  payload.Init()
+  if zipfile.is_zipfile(source):
+    source = zipfile.ZipFile(source)
+  if zipfile.is_zipfile(target):
+    target = zipfile.ZipFile(target)
+
+  old_partitions = []
+  new_partitions = []
+  expected_new_partitions = []
+  for part in payload.manifest.partitions:
+    name = part.partition_name
+    old_image = os.path.join(tempdir, "source_" + name + ".img")
+    new_image = os.path.join(tempdir, "target_" + name + ".img")
+    print("Extracting source image for", name)
+    extract_img(source, name, old_image)
+    print("Extracting target image for", name)
+    extract_img(target, name, new_image)
+
+    old_partitions.append(old_image)
+    scratch_image_name = new_image + ".actual"
+    new_partitions.append(scratch_image_name)
+    with open(scratch_image_name, "wb") as fp:
+      fp.truncate(part.new_partition_info.size)
+    expected_new_partitions.append(new_image)
+
+  delta_generator_args = ["delta_generator", "--in_file=" + payload_path]
+  partition_names = [
+      part.partition_name for part in payload.manifest.partitions
+  ]
+  delta_generator_args.append("--partition_names=" + ":".join(partition_names))
+  delta_generator_args.append("--old_partitions=" + ":".join(old_partitions))
+  delta_generator_args.append("--new_partitions=" + ":".join(new_partitions))
+
+  subprocess.check_output(delta_generator_args)
+
+  valid = True
+  for (expected_part, actual_part, part_name) in \
+      zip(expected_new_partitions, new_partitions, partition_names):
+    if filecmp.cmp(expected_part, actual_part):
+      print("Partition `{}` is valid".format(part_name))
+    else:
+      valid = False
+      print(
+          "Partition `{}` is INVALID expected image: {} actual image: {}"
+          .format(part_name, expected_part, actual_part))
+
+  if not valid and sys.stdout.isatty():
+    input("Paused to investigate invalid partitions, press any key to exit.")
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description="Run host side simulation of OTA package")
+  parser.add_argument(
+      "--source",
+      help="Target file zip for the source build",
+      required=True, nargs=1)
+  parser.add_argument(
+      "--target",
+      help="Target file zip for the target build",
+      required=True, nargs=1)
+  parser.add_argument(
+      "payload",
+      help="payload.bin for the OTA package, or a zip of OTA package itself",
+      nargs=1)
+  args = parser.parse_args()
+  print(args)
+
+  assert os.path.exists(args.source[0]), \
+    "source target file must point to a valid zipfile or directory"
+  assert os.path.exists(args.target[0]), \
+    "target path must point to a valid zipfile or directory"
+
+  # pylint: disable=no-member
+  with tempfile.TemporaryDirectory() as tempdir:
+    payload_path = args.payload[0]
+    if zipfile.is_zipfile(payload_path):
+      with zipfile.ZipFile(payload_path, "r") as zfp:
+        payload_entry_name = 'payload.bin'
+        zfp.extract(payload_entry_name, tempdir)
+        payload_path = os.path.join(tempdir, payload_entry_name)
+
+    run_ota(args.source[0], args.target[0], payload_path, tempdir)
+
+
+if __name__ == '__main__':
+  main()