I just had the heart stopping experience of a firmware flash failing, of course it was on my precious 3500. It appears as though no damage was done; I will know after a burn, but I thought I would pass it on so you can avoid it. It appears as though Binflash is not happy with firewire flashing using a Prolific chipset. A lot of people use this chip because it allows 16X burning.
All looked well until it got to erasing, step 2, and then it just froze with the drive light flashing. I went through all those things you say to yourself after a move that could have been avoided if I just wanted to open a few cases and move a few drives around and rebooted.
All looks well but, needless to say, the next firmware flash will be on a good old IDE cable. I am not sure if it was firewire or Prolific or Binflash and I don't plan to try again to find out.