Well, I was tempted to go to F15 again after restoring to see if it would work, but I was too angry to do so. Also, it seems they pulled the udpate anyway. My phone is no longer offering to go from F13 to F15. I`ll wait for the next update.Oh wow, that's sad to hear, I fixed my problems by simply reinstalling the OTA update KB2003_11_F.15 through the local update function.
I am now without root again but at least the phone is up-to-date, works and I got to keep my files.
Now I have to find out how to root the phone without breaking wifi and sound.