Thanks for the replies, guys!

I will try to send my N900 to Nokia. I don't loose anything, because if there are costs I can get it back without further costs.

Now my question. I heard Nokia has sensors built in their devices to monitor falls. They could be readout at the repair center. I have reflashed the device, and succesfully recovered the data.

Is there a way to 'reset' this sensor-counters? That would probably be my last way to succeed.

Any ideas on this one?