I was just thinking, with my N-Gage not booting up, that wouldn't it be possible to have a drive (such as the ROM Z😊 with all the system files backed up, and that the phone could recognize if it can't boot properly and prompt the user if he/she wants to restore original files, instead of having to take the phone to a Nokia Service Center or something.
Also backuping contacts, notes and calendar entries to either MMC or other drive should be a pre-installed function IMO.