I don't know if Macs even "do firmware updates".
Some do indeed, I had a couple to do on my iMac 400 before installing the newer versions of OSX. It involves doubleclicking the firmware update app, which shuts the mac down, and then holding down the programmer's interrupt button on the side while turning it back on.
The firmware updater immediately takes over, installs, then resets once more to boot with the new firmware installed.
It's -relatively- simple
dana
