diff --git a/platform/mb851/Makefile.mb851 b/platform/mb851/Makefile.mb851
index 1fd2b3a56..f1b127fde 100644
--- a/platform/mb851/Makefile.mb851
+++ b/platform/mb851/Makefile.mb851
@@ -28,4 +28,4 @@ endif
 
 
 login:
-	$(SERIALDUMP) -b115200 -d10000 $(DEV)
+	$(SERIALDUMP) -b115200 -d10000 $(PORT)