This page has installation instructions for an update to the BIOS. Assuming our G5 does not have Windows on it, can someone enlighten me as to how this works? Does it make a bootable USB stick for you to then plug into the G5? It won't try to flash the BIOS on whatever Windows computer you happen to have around, will it? All it says is a web page will open with more info, but I don't want to try installing it on a Windows machine until I know what it actually wants to do...
Update: forgot the link. I'm surprised this scored so high meanwhile :)
Use the HP Service Pack for ProLiant. It's a bootable DVD image, which will upgrade all the firmware on your server, including the BIOS.
If you don't have a DVD drive, or don't want to use one, you can use the HP USB Key Utility on a windows computer to create a bootable USB key from the image.
A third choice is to use the iLO console, and mount the image there. This would be the preffered choice, unless you're already standing right next to the server.