I did it via my PC and the Base 3 Sytem utility. Connected the PC network to the Base3 in AP mode with the base Switch set to AP and booted with the Gear/upgrade switch pressed in. Blinking light on the Base3 Did the update, took another couple of minutes for the base to reboot. Then I reconnected the computer to the Base3 AP network. To check everything.
If you have been running the Base3 on your home network/router. You need to go the the Base3 System Utility 'Configure" menu at the top to get it to find the IP address while in AP mode. Search option worked for me. 192.168.1.111 I think. Then you need to configure it back later in the Base 3 System Utility once you go back to the home network. Search worked for me then also.