diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index b6c96c4..08b4d6a 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -49,8 +49,8 @@
 # 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())
+    datetime.datetime(2009, 1, 1, 0, 0, 0, 0, datetime.UTC) -
+    datetime.datetime.fromtimestamp(0, datetime.UTC)).total_seconds())
 
 
 class BuildImageError(Exception):
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index b6cbb15..e5f5f92 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -2993,7 +2993,7 @@
     os.chmod(filename, perms)
 
     # Use a fixed timestamp so the output is repeatable.
-    # Note: Use of fromtimestamp rather than utcfromtimestamp here is
+    # Note: Use of fromtimestamp without specifying a timezone 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.