diff --git a/configs/at91sam9x5ek_mmc_defconfig b/configs/at91sam9x5ek_mmc_defconfig
index 863161e..0e30143 100644
--- a/configs/at91sam9x5ek_mmc_defconfig
+++ b/configs/at91sam9x5ek_mmc_defconfig
@@ -24,6 +24,7 @@
 # CONFIG_DISPLAY_BOARDINFO is not set
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="U-Boot> "
+CONFIG_SYS_CBSIZE=256
 CONFIG_SYS_PBSIZE=281
 CONFIG_CMD_BOOTZ=y
 # CONFIG_CMD_FLASH is not set