diff --git a/arch/arm/mach-imx/imx8ulp/soc.c b/arch/arm/mach-imx/imx8ulp/soc.c
index 1c33acc..bba6323 100644
--- a/arch/arm/mach-imx/imx8ulp/soc.c
+++ b/arch/arm/mach-imx/imx8ulp/soc.c
@@ -405,7 +405,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_SERIAL_TAG
+#ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 void get_board_serial(struct tag_serialnr *serialnr)
 {
 	u32 uid[4];