[Drew]

I have a G4 MDD 1.25 GHz and had the same happen to me and I just about freaked out because I thought that I had fried my ports for good - especially after using the hardware test and failing the motherboard test!! BUT, someone here suggested that I just try shutting down the computer, unplug it and let it sit for about 20 minutes, then startup and it worked like a charm. The firewire was reborn and the hardware test passed. It's worth a try before you start messing with resetting your motherboard.

I think I did it by unplugging my canopus box while it was turned on which is apparently a huge no-no. Anyways, I was very relieved and I'm now very very careful when I need to hot swap drives. I shut down and turn the canopus box off as I've become paranoid.

I hope it works for you.