diff --git a/configs/walnut_defconfig b/configs/walnut_defconfig
index 6880ae8..1e660ab 100644
--- a/configs/walnut_defconfig
+++ b/configs/walnut_defconfig
@@ -15,6 +15,7 @@
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_SNTP=y
+CONFIG_CMD_DIAG=y
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_SYS_NS16550=y