For next time, it's all about timing.
First, this will help (trying to press a recessed black button on time
with a pen is pretty difficult)
http://www.thingiverse.com/thing:27141
Then, the following process works reliably:
1. Go through the firmware upload screens until you get to the last
one with the "Upload button"
2. Position your mouse over the Upload button
3. Hit the reset button the replicator
4. WIthin 0.5seconds, hit the Upload button
5. Wait, you'll get no progress indication and it takes a while.
If it doesn't take you'll get a Timeout message in which case try
again.
Generally if you follow the above, it works first time. If it isn't
working for you after a few tries,
close RepG, disconnect the USB from the computer or bot, and restart
your computer. Then reconnect
the USB and try again. (sometimes the USB driver will lock up
preventing firmware update).
And after you've successfully updating the firmware, you'll need to
restart RepG to connect to the bot.
(at least on a Mac you do)