diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index 2b8d4ee..afb1c2f 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -182,13 +182,22 @@
     return False
   return True
 
+def Append(target, file_to_append, error_message):
+  cmd = 'cat %s >> %s' % (file_to_append, target)
+  print cmd
+  status, output = commands.getstatusoutput(cmd)
+  if status:
+    print "%s: %s" % (error_message, output)
+    return False
+  return True
+
 def BuildVerifiedImage(data_image_path, verity_image_path,
                        verity_metadata_path):
-  if not Append2Simg(data_image_path, verity_image_path,
-                     "Could not append verity tree!"):
+  if not Append(verity_image_path, verity_metadata_path,
+                "Could not append verity metadata!"):
     return False
-  if not Append2Simg(data_image_path, verity_metadata_path,
-                     "Could not append verity metadata!"):
+  if not Append2Simg(data_image_path, verity_image_path,
+                     "Could not append verity data!"):
     return False
   return True