diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index fea335e..efba1fe 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -498,6 +498,8 @@
   if target.endswith(".img"): target = target[:-4]
   mount_point = "/" + target
 
+  fs_type = None
+  limit = None
   if info_dict["fstab"]:
     if mount_point == "/userdata": mount_point = "/data"
     p = info_dict["fstab"][mount_point]