I had to replace my 6 plus (jail broken) with a new 7 plus. I have had it a week, had problems with siri so they had me update the phone to try and fix it. When that happen I was now at 10.2.1 witch I did not want.So my question is if I restore the phone back to factory will it still have 10.2.1 or will it go back to what it was when I first got it?