Try installing the cores for the "Arduino megaAVR boards" in the Board manager. After installation you can select the board by Tools > Board > Arduino Uno WiFI Rev2
Then you should be able to do a Firmware update.
Try installing the cores for the "Arduino megaAVR boards" in the Board manager. After installation you can select the board by Tools > Board > Arduino Uno WiFI Rev2
Then you should be able to do a Firmware update.