diff --git a/board/kup4k/flash.c b/board/kup4k/flash.c
index 3837457..7297c15 100644
--- a/board/kup4k/flash.c
+++ b/board/kup4k/flash.c
@@ -74,7 +74,7 @@
 	/* monitor protection ON by default */
 	flash_protect(FLAG_PROTECT_SET,
 		      CFG_MONITOR_BASE,
-		      CFG_MONITOR_BASE+CFG_MONITOR_LEN-1,
+		      CFG_MONITOR_BASE+monitor_flash_len-1,
 		      &flash_info[0]);
 #endif