diff --git a/toolkit/mozapps/installer/informulate.py b/toolkit/mozapps/installer/informulate.py
index 1799c683de88..6af43ac6857a 100644
--- a/toolkit/mozapps/installer/informulate.py
+++ b/toolkit/mozapps/installer/informulate.py
@@ -14,7 +14,7 @@ def parse_cmdline(args):
     contents = {}
     for arg in args:
         key, s, value = arg.partition("=")
-        if value == '':
+        if s == '':
             print "ERROR: Malformed command line key value pairing (%s)" % arg
             exit(1)
         contents[key.lower()] = value