I have to confess that this is the second time I've tried to update the firmware. The first time, a week ago with the 5.4 beta, I just couldn't do it. I called Makerbot support and after a few tries they basically said to wait a week because it was closing time for them (oops, time zones) and they were rolling out a new version soon. So I guess thanks to Makerbot support for that good call. Not quite sure they get credit for making it work but at least I'm a tenth of a version number higher than I would have been if I had succeeded a week ago.
I've got to run some tests after work today to make sure everything's good but once this works I should be able to print a full chess set in a little over 2 hours. Here's hopin'.