I just finished replacing in battery in my wife's iPhone 5s. This is my first project with ifixit. I went by the video, not realizing the guides were available until I had completed it and was about to turn it on. I was HORRORIFED to learn the fours screws at top that hold down the screen connectors are DIFFERENT SIZES and have to go back into the hole they came out of or it could DAMAGE THE LOGIC BOARD!!!! That was never mentioned in the video!! The phone seems very slow down and is not downloading quickly on a known fast connection so I am not happy that such a critical detail was passed over in the video. Perhaps I have damaged the logic board after all.