diff --git a/arch/arm/mach-imx/imx8/cpu.c b/arch/arm/mach-imx/imx8/cpu.c
index 02db322..ee5cc47 100644
--- a/arch/arm/mach-imx/imx8/cpu.c
+++ b/arch/arm/mach-imx/imx8/cpu.c
@@ -172,7 +172,7 @@
 	return boot_dev;
 }
 
-#ifdef CONFIG_SERIAL_TAG
+#ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 #define FUSE_UNIQUE_ID_WORD0 16
 #define FUSE_UNIQUE_ID_WORD1 17
 void get_board_serial(struct tag_serialnr *serialnr)
@@ -201,7 +201,7 @@
 	serialnr->low = val1;
 	serialnr->high = val2;
 }
-#endif /*CONFIG_SERIAL_TAG*/
+#endif /*CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG*/
 
 #ifdef CONFIG_ENV_IS_IN_MMC
 __weak int board_mmc_get_env_dev(int devno)