diff --git a/aosp_diff/caas/build/make/0001-use-a-dynamic-timestamp.patch b/aosp_diff/caas/build/make/0001-use-a-dynamic-timestamp.patch
new file mode 100644
index 0000000000..dea652c1b3
--- /dev/null
+++ b/aosp_diff/caas/build/make/0001-use-a-dynamic-timestamp.patch
@@ -0,0 +1,65 @@
+From 20dd4a9b4c0fb0b18f0659a7bcc2e996699ecf51 Mon Sep 17 00:00:00 2001
+From: "jialei.feng" <jialei@otc-aes-1604>
+Date: Tue, 13 Oct 2020 10:00:34 +0800
+Subject: [PATCH] use a dynamic timestamp
+
+Signed-off-by: jialei.feng <jialei@otc-aes-1604>
+---
+ tools/releasetools/add_img_to_target_files.py | 13 -------------
+ 1 file changed, 13 deletions(-)
+
+diff --git a/tools/releasetools/add_img_to_target_files.py b/tools/releasetools/add_img_to_target_files.py
+index eb041ecea..f85c9dfb3 100644
+--- a/tools/releasetools/add_img_to_target_files.py
++++ b/tools/releasetools/add_img_to_target_files.py
+@@ -46,7 +46,6 @@ Usage:  add_img_to_target_files [flag] target_files
+ 
+ from __future__ import print_function
+ 
+-import datetime
+ import logging
+ import os
+ import shlex
+@@ -76,13 +75,6 @@ OPTIONS.replace_verity_public_key = False
+ OPTIONS.replace_verity_private_key = False
+ OPTIONS.is_signing = False
+ 
+-# Use a fixed timestamp (01/01/2009 00:00:00 UTC) for files when packaging
+-# images. (b/24377993, b/80600931)
+-FIXED_FILE_TIMESTAMP = int((
+-    datetime.datetime(2009, 1, 1, 0, 0, 0, 0, None) -
+-    datetime.datetime.utcfromtimestamp(0)).total_seconds())
+-
+-
+ class OutputFile(object):
+   """A helper class to write a generated file to the given dir or zip.
+ 
+@@ -399,7 +391,6 @@ def CreateImage(input_dir, info_dict, what, output_file, block_list=None):
+   logger.info("creating %s.img...", what)
+ 
+   image_props = build_image.ImagePropFromGlobalDict(info_dict, what)
+-  image_props["timestamp"] = FIXED_FILE_TIMESTAMP
+ 
+   if what == "system":
+     fs_config_prefix = ""
+@@ -471,8 +462,6 @@ def AddUserdata(output_zip):
+ 
+   logger.info("creating userdata.img...")
+ 
+-  image_props["timestamp"] = FIXED_FILE_TIMESTAMP
+-
+   if OPTIONS.info_dict.get("userdata_img_with_data") == "true":
+     user_dir = os.path.join(OPTIONS.input_tmp, "DATA")
+   else:
+@@ -562,8 +551,6 @@ def AddCache(output_zip):
+ 
+   logger.info("creating cache.img...")
+ 
+-  image_props["timestamp"] = FIXED_FILE_TIMESTAMP
+-
+   user_dir = common.MakeTempDir()
+   build_image.BuildImage(user_dir, image_props, img.name)
+ 
+-- 
+2.17.1
+