Epson 3880 Maintenance Mode Problem
The reason I didn't see how to update the firmware is that it isn't a download option on the Epson website if it detects you are running recent versions of Mac OS X. I tried to run the Remote Panel Utility on Windows 7 but for some reason the tool can't detect the networked printer. I can print from Windows 7 though, so the driver installed OK.
I don't understand Epson's version numbering scheme, so it wasn't obvious that the version on their website is newer than what I have. If I can get the updater to work I might give the newer version a try, but it's curious that you don't seem to have the power down option menu either so maybe not worth the risk.