Chosen Solution

Hello, I replaced the screen on an iPhone 6s with an original (refurbished) replacement part. Since the repair, everytime I boot the phone, after a few seconds the screen goes black, then the apple logo appears again and it boots normally and works perfect most time, sometimes the touch isn’t working, then I have to lock and unlock the phone and everything works fine. What could the issue be?

Is the phone on iOS 11? There are lot’s of folks complaining about strange issues with the iPhone 6S and iSO 11. The worst case is when Touch fails completely. I wrote up an article on this; you can go to my profile for a link if your curious. Seeing as how your replacement screen is a refurbished original, it should have a proper Touch controller on the flex. That said, I would try another screen to see if the issue persists.

In iOS11, it is normal for it to blank for a second during boot, it happens on every iOS 11 phone I’ve seen including my own phone (all original and unopened). Make sure you have upgraded to iOS 11.0.3, as it specifically says in the notes that Apple fixed an issue where the 6S would freeze when not serviced with genuine Apple parts. https://9to5mac.com/2017/10/11/ios-11-0-