I have also fixed 1000s of iphone dating back to 2009 and never once did i have to do that as well but if you kno anything about electronics the hardware was just simply not compatible i tried a different screen and the samething would happen just instead of red it would go blue and so did the original as soon as i restored with original apple parts things work fine customer very happy thank you and i did the restore with the phone open and no emi shield and it still worked

hey tom just encountered the same thing i hope this helps cause it helped me i bought a replacement screen with all the attachments when i replaced it the phone would flash red and then reboot it would continually do this till it finally booted up the customer then took phone home when phone died and try to charge it would go to the red screen i put back the original it would stay on longer but then reboot to a blue screen now its important to make sure that it turns blue or the original is back on. Now what you do is restore the iphone when your booting it up hold the home button and power button at same time until its in dfu mode while connected to pc or mac then restore iphone after that it should work i bought a another screen but one that i need to transfer all the parts too. I think since the screen i bought had all the non-apple parts the hardware messed up the phone so with the new screen transfer the parts son the only thing that is not original is the screen. It worked for me it should work for you