diff --git a/smart/transaction.py b/smart/transaction.py
index 4b90cb7..bb65b7a 100644
--- a/smart/transaction.py
+++ b/smart/transaction.py
@@ -1028,7 +1028,8 @@ def _upgrade(self, pkgs, changeset, locked, pending, depth=0):
         for pkg in changeset.keys():
 
             op = changeset.get(pkg)
-            if (op and op != origchangeset.get(pkg) and
+	    origpkgop = origchangeset.get(pkg)
+            if (op and origpkgop != None and op != origpkgop and
                 pkg not in locked and pkg not in lockedstates):
 
                 try: