diff --git a/board/siemens/pcu_e/flash.c b/board/siemens/pcu_e/flash.c
index b8c0df7..05c364b 100644
--- a/board/siemens/pcu_e/flash.c
+++ b/board/siemens/pcu_e/flash.c
@@ -148,7 +148,7 @@
 	/* monitor protection ON by default */
 	flash_protect(FLAG_PROTECT_SET,
 		      PCU_MONITOR_BASE,
-		      PCU_MONITOR_BASE+CFG_MONITOR_LEN-1,
+		      PCU_MONITOR_BASE+monitor_flash_len-1,
 		      &flash_info[0]);
 
 #ifdef	CFG_ENV_IS_IN_FLASH