diff --git a/configs/tb100_defconfig b/configs/tb100_defconfig
index 0adf050..7b843a7 100644
--- a/configs/tb100_defconfig
+++ b/configs/tb100_defconfig
@@ -2,6 +2,7 @@
 CONFIG_TARGET_TB100=y
 CONFIG_SYS_TEXT_BASE=0x84000000
 CONFIG_SYS_MALLOC_LEN=0x20000
+CONFIG_SYS_MALLOC_F_LEN=0x400
 CONFIG_ENV_SIZE=0x800
 CONFIG_DEFAULT_DEVICE_TREE="abilis_tb100"
 CONFIG_SYS_CLK_FREQ=500000000