Cause: You downloaded a version for the wrong chipset (e.g., trying to put AC firmware on an M-series device).
Solution: Redownload the file specifically for AirMax M (AR934x), not AirMax AC.
You have the file, and your device is ready. Here are the three proven methods to flash version 1.255. Upgrade Firmware Version 1.255 Ubnt -FREE- Download
A: Yes. Ubiquiti has never charged for firmware updates. Any website asking for payment or "premium access" is a scam. Cause: You downloaded a version for the wrong chipset (e