$(MKBOOTFS) $(dir $(dir $(<D))) | gzip -9 > $@
boot_dir := $(PRODUCT_OUT)/boot
-$(boot_dir): $(wildcard $(LOCAL_PATH)/boot/isolinux/*) $(systemimg) $(GENERIC_X86_CONFIG_MK) | $(ACP)
+$(boot_dir): $(shell find $(LOCAL_PATH)/boot -type f | sort -r) $(systemimg) $(GENERIC_X86_CONFIG_MK) | $(ACP)
$(hide) rm -rf $@
$(ACP) -pr $(dir $(<D)) $@