A progress bar will appear. the device during this time, as it can "brick" the router.
Look at the PCB silkscreen or the label on the back. If it says "AOT4221SR V2.0" or V3.0, the firmware file will differ. Proceeding with the wrong firmware is the #1 cause of bricks. aot4221sr firmware upgrade
: Log back into the management interface and verify that the firmware version number now reflects the newly installed version. A progress bar will appear
Ensure the file extension matches the requirements (typically .bin , .img , or .tar.gz ). or .tar.gz ).