twice from 0s2007-->os2008. Then flashed again for the newer os2008.
and then...I typed in a command that the terminal suggested and I saw my n800 saying removing..._____ like a million times and then when my device shut down, I realized what had happened and reflashed it with os2008. Backups have become my new best friend.
The two times I needed to reflash, one due to theming issues and the other due to theming issues, I didn't make a backup. I need a little warning message to go off telling me to back up when it senses that I'm doing something stupid. If anyone can make an app for that, I'd be eternally grateful.
I have several devices so I just put what I think is the average. I have one testbed N800 that gets flashed almost weekly so it's hard to really say...