If it has something to do with this situation and my warranty etc, I'd like to add that the phone was in developer mode and I had installed two non-store apps (FM radio and vlc, which I have already removed). Also the 'allow third party installations' etc option was thus enabled. Enabling the developer mode and that other switch should have nothing to do with voiding warranties, right? That would be highly bizarre, as these are option that I can control from the UI.

On more detail that came into my mind is that I could not access the system settings at all before that fatal boot. The phone is cyan N9 16Gb, and bought from Finland.