Share your experience!
Uli,for SP it does not work like that.
How did you change the playback option?Did you listen to a song and tap longer on the album art to get those options?
I stand corrected
I thought it was like the Xperia Z1 that you have both options either press and hold power & volume up for 5 seconds or press and hold the red button
He was talking about force restart(but it cannot be done like that in SP).You need to press little red button on the back of the phone.
I am sorry to say this,but I think you need a software repair.Sadly,this will erase all your phone memory.