[OpenWrt Wiki] Rescue from failed firmware upgrade
openwrt.org › docs › guide-userOpenWrt devices that use a drive-installed image.gz or sdcard.img.gz are not an issue to recover. The OpenWrt OS is not applied to flash ROM, but installed on a removable drive, e.g. an SD-card. For recovery, mount the removable drive in a working PC and reapply the OpenWrt image to the removable drive according to the device-specific instructions.