Your unit works perfectly. Many F9212B updates are minor MCU revisions that offer no noticeable benefit but risk breaking something.
Look for entries like:
: Keep the engine running during the process (which takes about 7 minutes) to prevent power loss. 2. Over-the-Air (OTA) / App Updates Some units support direct updates if connected to Wi-Fi. f9212b android update
If the device keeps asking to update, remove the USB drive after the first reboot. Your unit works perfectly
Perhaps the most important advice is this: before you start any update, always dump your stock firmware as a backup. Users on 4PDA and XDA who have installed custom recoveries like TWRP can create a full system backup to revert to if anything goes wrong. f9212b android update