Sometimes initrd.img doesn't generate correctly so the iso can't boot.
Fix it by adding mkbootfs to be an order-only prerequisite of initrd.img.
$(wildcard $(initrd_dir)/*/*)
installer_ramdisk := $(PRODUCT_OUT)/initrd.img
-$(installer_ramdisk): $(initrd_bin) | $(ACP)
+$(installer_ramdisk): $(initrd_bin) | $(ACP) $(MKBOOTFS)
rm -rf $(TARGET_INSTALLER_OUT)
$(ACP) -pr $(initrd_dir) $(TARGET_INSTALLER_OUT)
ln -s /bin/ld-linux.so.2 $(TARGET_INSTALLER_OUT)/lib