diff --git a/configs/opos6uldev_defconfig b/configs/opos6uldev_defconfig
index 2d0a065..cdb246f 100644
--- a/configs/opos6uldev_defconfig
+++ b/configs/opos6uldev_defconfig
@@ -20,6 +20,7 @@
 CONFIG_ENV_OFFSET_REDUND=0x180000
 CONFIG_SPL_LIBDISK_SUPPORT=y
 # CONFIG_CMD_BMODE is not set
+CONFIG_SYS_MONITOR_LEN=409600
 CONFIG_SUPPORT_RAW_INITRD=y
 CONFIG_BOOTDELAY=5
 CONFIG_USE_BOOTARGS=y