Update Makefile
diff --git a/Makefile b/Makefile
index df241bb..61b80c7 100644
--- a/Makefile
+++ b/Makefile
@@ -38,7 +38,7 @@
 ifeq ($(PDK),sky130B)
 	SKYWATER_COMMIT=f70d8ca46961ff92719d8870a18a076370b85f6c
 	OPEN_PDKS_COMMIT?=41c0908b47130d5675ff8484255b43f66463a7d6
-	OPENLANE_TAG=2022.07.02_01.38.08
+	OPENLANE_TAG?=2022.07.02_01.38.08
 
 ifeq ($(CARAVEL_LITE),1)
 	CARAVEL_NAME := caravel-lite