diff --git a/tools/releasetools/add_img_to_target_files.py b/tools/releasetools/add_img_to_target_files.py
index bc2667d..6bdb9d1 100755
--- a/tools/releasetools/add_img_to_target_files.py
+++ b/tools/releasetools/add_img_to_target_files.py
@@ -28,6 +28,7 @@
   print >> sys.stderr, "Python 2.7 or newer is required."
   sys.exit(1)
 
+import datetime
 import errno
 import os
 import shutil
@@ -120,6 +121,12 @@
   if fstab:
     image_props["fs_type"] = fstab["/" + what].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)
+
   if what == "system":
     fs_config_prefix = ""
   else:
@@ -166,6 +173,12 @@
 
   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)
+
   # The name of the directory it is making an image out of matters to
   # mkyaffs2image.  So we create a temp dir, and within it we create an
   # empty dir named "data", or a symlink to the DATA dir,
@@ -210,6 +223,12 @@
 
   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)
+
   # The name of the directory it is making an image out of matters to
   # mkyaffs2image.  So we create a temp dir, and within it we create an
   # empty dir named "cache", and build the image from that.
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index e1488dc..e5e2a24 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -20,7 +20,6 @@
 Usage:  build_image input_directory properties_file output_image_file
 
 """
-import datetime
 import os
 import os.path
 import re
@@ -387,11 +386,10 @@
   """
   d = {}
 
-  # Use a fixed timestamp (01/01/2009) for all the files in an image.
-  # Bug: 24377993
-  epoch = datetime.datetime.fromtimestamp(0)
-  timestamp = (datetime.datetime(2009, 1, 1) - epoch).total_seconds()
-  d["timestamp"] = int(timestamp)
+  if "build.prop" in glob_dict:
+    bp = glob_dict["build.prop"]
+    if "ro.build.date.utc" in bp:
+      d["timestamp"] = bp["ro.build.date.utc"]
 
   def copy_prop(src_p, dest_p):
     if src_p in glob_dict: