Hi, for your concern, indeed my iPhone 6 restarts and then automatically launches whatever app was previously on the screen, usually several of them and no one lost with the restart action. But nothing special with Apple boot screen, just like a normal restart, but...the thing is I don't give it a reboot order...
PS: I didn't update to newest iOS, just keep 8.1 version, cuz I think its the best to keep the original one, so that there's no app compatibility problem afterwards. Is this the possible reason for the restart phenomenon?
Haven't tried the recovery mode, I'll update the outcome here after done it.