Chosen Solution
Tips/tricks appreciated. -I replaced the battery, but now the screen is/remains black. I have no evidence it is turning on (no noises/vibrate/etc). It’s been “charging” for an hour now, but no change, just a blank, black screen. -I got an Ifixit battery and followed the guides (while looking online quickly for some notes). The only thing I did not do is remove the screen, I rubber-banded it to a box and just kept it up at a 90* angle while working. Does it sound like the screen/connectors got damaged? -I also had a very hard time removing the previous battery and had to pry it out, but it does not seem like I had hit anything or bent anything while doing this. Had to use a hair dryer to loosen the adhesive, so any created some static electricity and damaged something? (I closed the phone for this part) However, the battery definitely got bent and it probably wouldn’t be a good idea to plug it in again. -Additional information below with answers.
I’d recommend trying to remove the upper shield covering the cables connectors and reconnect cables to the logic board. If you removed battery with screen in place there’s a chance connectors moved out of place, hopefully not damaged but that’s a possibility too. If you have a PC connect the iPhone to it with iTunes open, it will get recognized if it’s booting fine.
