It seems I just managed to wedge my N810 by installing / updating some software. The symptoms are:

N810 boots (the Nokia logo with the blue progress bar appears), then it asks to enter the lock code. I enter the lock code, then the Nokia logo comes on again and after a couple of seconds, the LEDs start to light up and then the tablet reboots. Lather, rinse, repeat.

I guess something is borked in the startup sequence of applications -- is there a way to do some kind of "safe boot", where it doesn't try to start any user installed apps or is the only way to get out of this a re-flash?

Cheers,

mjl