diff --git a/libsrc/cbm510/crt0.s b/libsrc/cbm510/crt0.s
index 15335a1e9..ae4f82105 100644
--- a/libsrc/cbm510/crt0.s
+++ b/libsrc/cbm510/crt0.s
@@ -274,7 +274,7 @@ Z4:
 	lda	(vic),y
 	sta	vidsave+2
 	and	#$0F
-       	ora    	#<(((>__VIDRAM_START__) & $3F) << 2)
+       	ora    	#<(((>__VIDRAM_START__) << 2) & $F0)
 	sta	(vic),y
 
 ; Switch back to the execution bank