I tend to always update to the latest bios version through windows and touch wood I've never encountered a problem yet!
Gigabyte do a nice little utility called
@BIOS which allows you to do live updates over the internet by connecting to their servers, and its very easy to use. Start the utility up and save your current bios first, then click on the “Update bios from Gigabyte server” The whole process takes a few minutes and if you do encounter any problems you use the same programme to restore your backed-up bios.
LINK
Turk.