LOOKS LIKE, If I remembered correctly now that I read somewhere here in the foruns, that if we left the n900 still in the tablet position ON A TABLE, it will reboot, and in fact sometimes I keep trying and it reboots after 2 or 3 tries and then If I let it there still in the position that I got it rebooting, it will reboot forever. BUT, If I move it, it will stop rebooting.

REALLY strange. Try it. Put it in the tablet position with the thing on the lens opened (not the lens cover, that other thing that makes it not just fall, at around 35º). Then try a reboot. What happens?

PS: I just tried, laid it in the tablet position on a table with that thing that surround the lens in the 35º. 2º reboot try: Rebooted. From now on it will reboot until I move it.