diff --git a/configs/sandbox_flattree_defconfig b/configs/sandbox_flattree_defconfig
index 5980c86..edfdac8 100644
--- a/configs/sandbox_flattree_defconfig
+++ b/configs/sandbox_flattree_defconfig
@@ -107,6 +107,7 @@
 CONFIG_I2C_ARB_GPIO_CHALLENGE=y
 CONFIG_CROS_EC_KEYB=y
 CONFIG_I8042_KEYB=y
+CONFIG_IOMMU=y
 CONFIG_LED=y
 CONFIG_LED_BLINK=y
 CONFIG_LED_GPIO=y