diff --git a/include/image.mk b/include/image.mk
index be1b6f4d27..2d6550841d 100644
--- a/include/image.mk
+++ b/include/image.mk
@@ -187,7 +187,8 @@ ifneq ($(CONFIG_NAND_SUPPORT),)
 	[ -z "$(3)" ] || $(CP) "$(3)" "$(KDIR_TMP)/sysupgrade-$(1)/kernel"
 	(cd "$(KDIR_TMP)"; $(TAR) cvf \
 		"$(BIN_DIR)/$(IMG_PREFIX)-$(1)-$(2)-sysupgrade.tar" sysupgrade-$(1) \
-			$(if $(SOURCE_DATE_EPOCH),--mtime="@$(SOURCE_DATE_EPOCH)")
+			$(if $(SOURCE_DATE_EPOCH),--mtime="@$(SOURCE_DATE_EPOCH)") \
+	)
    endef
 
 # $(1) board name