diff --git a/scripts/update_payload/checker.py b/scripts/update_payload/checker.py
index 7a319f7..15f11ae 100644
--- a/scripts/update_payload/checker.py
+++ b/scripts/update_payload/checker.py
@@ -1397,7 +1397,8 @@
       used_payload_size = self.payload.data_offset + total_blob_size
       # Major versions 2 and higher have a signature at the end, so it should be
       # considered in the total size of the image.
-      if self.major_version >= common.BRILLO_MAJOR_PAYLOAD_VERSION:
+      if (self.major_version >= common.BRILLO_MAJOR_PAYLOAD_VERSION and
+          self.sigs_size):
         used_payload_size += self.sigs_size
 
       if used_payload_size != payload_file_size: