The download here has the current firmware as well as instructions-
Rive also has a post that provides a pretty good demo on firmware updating.
http://www.2gigforum.com/threads/1-(Mirror)-Download-2GIG-GO!Control-Firmware
There is a link on our product page for firmware updates that we add to as more releases are made available, in case you’re looking for future updates down the road. Let us know if you have any questions in the process.