diff --git a/meta-digi-arm/recipes-kernel/linux/linux-dey.inc b/meta-digi-arm/recipes-kernel/linux/linux-dey.inc
index 725c2485c..19c71f113 100644
--- a/meta-digi-arm/recipes-kernel/linux/linux-dey.inc
+++ b/meta-digi-arm/recipes-kernel/linux/linux-dey.inc
@@ -33,7 +33,7 @@ UBOOT_CONFIG_LOADADDR_ccimx6 = "0x12000000"
 UBOOT_CONFIG_LOADADDR_ccimx6ul = "0x80800000"
 
 do_deploy_append() {
-	if [ -n "${TRUSTFENCE_SIGN}" ]; then
+	if [ "${TRUSTFENCE_SIGN}" = "1" ]; then
 		export CONFIG_SIGN_KEYS_PATH="${TRUSTFENCE_SIGN_KEYS_PATH}"
 		export CONFIG_UIMAGE_LOADADDR="${UBOOT_CONFIG_LOADADDR}"
 		[ -n "${TRUSTFENCE_KEY_INDEX}" ] && export CONFIG_KEY_INDEX="${TRUSTFENCE_KEY_INDEX}"