Chosen Solution
My iPhone 6s has a really bad dent and when it got it, it stopped working, is there a way to make it work. Even if it just works for one iTunes backup. It has some data I really need from the day it died. And can I know what exactly got damaged?
There is no way of knowing what component has been damaged from the dent. The only thing you could try would be to rule out parts. Try a replacement battery and screen and make sure all the connectors are sitting firmly, other than that you would need a multimeter and DCPS to find the faulty component.
