Ok i work for celulap and we had the same issue here so iphone 6 and 6 plus have a serialised Screen and there for You must do the restore with its orginal screen if you must do the restore.
so if you have a iphone six with that error message there has been a screen replacement. and the screen that you are replacing it not a genuine screen now in days if you got a cheap screen replacement that is going to be the case.thanks and good luck just do restore with original screen and home button and walla.bingo was its namo.