diff --git a/board/netstal/hcu4/hcu4.c b/board/netstal/hcu4/hcu4.c
index c144741..aa8a097 100644
--- a/board/netstal/hcu4/hcu4.c
+++ b/board/netstal/hcu4/hcu4.c
@@ -134,7 +134,7 @@
  */
 u32 get_serial_number(void)
 {
-	u32 serial = in_be32((u32 *)CFG_FLASH_BASE);
+	u32 serial = in_be32((u32 *)CONFIG_SYS_FLASH_BASE);
 
 	if (serial == 0xffffffff)
 		return 0;