Originally Posted by
intuition
And again, exactly my take. Early checkin online. If BP cannot be printed at that time, make sure to get BP as pdf in computer or phone or final option as text message. At airport, get hard copy of BP at machine or desk. Never ever get BP into any kind of app.
For instance, the Norwegian app has never let me down when it comes to boarding passes. Again, it's otherwise quite buggy as most of the cheap-made iOS apps. Anyway, I don't think one has to worry much about his mobile boarding pass. Should it fail, can the gate agent always find it with the booking reference etc. Also the Passbook boarding passes Finnair introduced a while ago are quite trustable as far as I know as Passbook is iOS' native app.