diff --git a/tools/releasetools/add_img_to_target_files.py b/tools/releasetools/add_img_to_target_files.py
index f7324bd..0d9c79b 100755
--- a/tools/releasetools/add_img_to_target_files.py
+++ b/tools/releasetools/add_img_to_target_files.py
@@ -72,10 +72,12 @@
 OPTIONS.replace_verity_private_key = False
 OPTIONS.is_signing = False
 
-
 # Partitions that should have their care_map added to META/care_map.txt.
 PARTITIONS_WITH_CARE_MAP = ('system', 'vendor', 'product', 'product-services')
-
+# Use a fixed timestamp (01/01/2009 00:00:00 UTC) for files when packaging
+# images. (b/24377993, b/80600931)
+FIXED_FILE_TIMESTAMP = (datetime.datetime(2009, 1, 1, 0, 0, 0, 0, None)
+                        - datetime.datetime.utcfromtimestamp(0)).total_seconds()
 
 class OutputFile(object):
   def __init__(self, output_zip, input_dir, prefix, name):
@@ -94,7 +96,6 @@
     if self._output_zip:
       common.ZipWrite(self._output_zip, self.name, self._zip_name)
 
-
 def GetCareMap(which, imgname):
   """Returns the care_map string for the given partition.
 
@@ -259,11 +260,7 @@
   if fstab and mount_point in fstab:
     image_props["fs_type"] = fstab[mount_point].fs_type
 
-  # Use a fixed timestamp (01/01/2009) when packaging the image.
-  # Bug: 24377993
-  epoch = datetime.datetime.fromtimestamp(0)
-  timestamp = (datetime.datetime(2009, 1, 1) - epoch).total_seconds()
-  image_props["timestamp"] = int(timestamp)
+  image_props["timestamp"] = FIXED_FILE_TIMESTAMP
 
   if what == "system":
     fs_config_prefix = ""
@@ -337,11 +334,7 @@
 
   print("creating userdata.img...")
 
-  # Use a fixed timestamp (01/01/2009) when packaging the image.
-  # Bug: 24377993
-  epoch = datetime.datetime.fromtimestamp(0)
-  timestamp = (datetime.datetime(2009, 1, 1) - epoch).total_seconds()
-  image_props["timestamp"] = int(timestamp)
+  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")
@@ -483,11 +476,7 @@
 
   print("creating cache.img...")
 
-  # Use a fixed timestamp (01/01/2009) when packaging the image.
-  # Bug: 24377993
-  epoch = datetime.datetime.fromtimestamp(0)
-  timestamp = (datetime.datetime(2009, 1, 1) - epoch).total_seconds()
-  image_props["timestamp"] = int(timestamp)
+  image_props["timestamp"] = FIXED_FILE_TIMESTAMP
 
   user_dir = common.MakeTempDir()
 
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index c10e57c..89b4037 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1271,8 +1271,12 @@
     os.chmod(filename, perms)
 
     # Use a fixed timestamp so the output is repeatable.
-    epoch = datetime.datetime.fromtimestamp(0)
-    timestamp = (datetime.datetime(2009, 1, 1) - epoch).total_seconds()
+    # Note: Use of fromtimestamp rather than utcfromtimestamp here is
+    # intentional. zip stores datetimes in local time without a time zone
+    # attached, so we need "epoch" but in the local time zone to get 2009/01/01
+    # in the zip archive.
+    local_epoch = datetime.datetime.fromtimestamp(0)
+    timestamp = (datetime.datetime(2009, 1, 1) - local_epoch).total_seconds()
     os.utime(filename, (timestamp, timestamp))
 
     zip_file.write(filename, arcname=arcname, compress_type=compress_type)