Not taking qwerty's warning, I upgraded my N810 to the latest packages. This also caused my tablet to stop booting. Oops.

However, as I was trying to flash Chinook back onto it my computer got too slow (just finishing booting and starting firefox, thunderbird, vmware player, and outlook while trying to flash) and the flash hung. I unplugged the USB cable to start over and lo! the tablet booted. All my apps are still installed and settings intact AND the control panel says the version is 4.2008.21-4 and gave me an "Update successful" message.

Probably not reproducible unless you just need to bring it into USB flash mode and then reboot. Maybe this will help someone stuck after the update.