wifi connection keeps cutting out how to update firmware - G34

The Cable Operators (MSOs) have complete control of what cable modem/gateway hardware they will allow installed and the firmware it uses, this is because they own the coaxial cable that is connected to the ARRIS G34, because of that the Firmware updates are pushed by them, and any update needed as well. Any associated firmware updates are automatically deployed by the cable operator. This is not an ARRIS only implementation, but the required implementation of any cable device manufacturer.

For intermittent connection issue you can try changing WIFI channels for respective network by following the steps mentioned on the below article and monitor connection for next 24hrs.

http://arris.force.com/consumers/articles/General_FAQs/G34-G36-Changing-the-Wi-Fi-Channel

You need to use surfboard central application to check on your modem and if you get any error on the app or connection failure just toggle the WIFI network on your m=device then continue on the app to complete setup.