Chosen Solution
So I was replacing the battery of a friends iPhone 6s. During disassembly I noticed that there was damage to the phones screen - the film which is protecting the thermal paste, or whatever that silvery stuff is, had been damaged. The damage had occurred over the magnetic part below the battery port. Now the phone doesn’t seem to be turning on. I plugged the phone in to charge it after I had exchanged the battery and it got really hot quickly. Now I have the old battery in the phone and it is still not turning on. Any advice on how to fix this would be appreciated.
If you used a particularly cheap battery it can cause problems. The damage to that metal plate is harmless and unrelated to your issue. Where did you buy that replacement battery from?
