I also had a button that wasn’t working well. This is why I tried to disassemble it. Since these days of confinment I did it again but followed a little more, I can recommend you that you won’t see anything since it is like a laptop keyboard also you also can damage the black label that is very sticked. This 2nd time when I did this process, I melted down one button (the left arrow) and now it is deformed and I had to repair it.
Since the keys mechanism is same as on laptop keyboards, you can try to pull it up by the one side and then the other side with care to don’t damage it.
In my case, the problem was dirty under the button that was sticking the membrane each pushin. I cleaned with alcohol and a small brush and restore it’s functionality.
EN: The lateral small plastic piece is sticked to the flex of the side buttons. Take care
right. it has 4 strips of adhesive tape
The guide is incomplete as some important steps aren’t well explained or they weren’t even explained. In general, the guide is good
Thanks to the autor
If you wont put a new battery, take care how you unstick the original / old one. It’s too well glued. Heat it well by the screen side using the iOpener or simial gel back pre-heated in the MWO. Use some plastic flat too to breake the glue. The battery will get deformed. I straghted it back and it seems to keep working.
My new frame came with this glue new and covered with a plastic. I didn’t removed that plastic in case the battery is damaged while taking out and it has to be replaced.
Attention: The flex with the buttons is well sticked to the frame. Take care how you are removing it. Use a thin tool and try to release the stick with a caution to don’t damage the flex. Pull slowly the flex.
If you breake it, you won’t be able to turn on the phone
The motherboard is also fixed to the frame with clips. Pull it by the right side. It also hase thermal paste which could act as a sticking solution. I cleaned the one which remains on the motherboard and added another new which is being used on computers
It will be easier to put it back if releasing by the other side of the flex cable which is under the metallic cover of usb charging board, fingerprint reader and battery connector and fixed with two screws (metallic plate above the black flex cable)
I editted this guide and added these two comments. I already know about this “trick”. It’s your own decision to follow my suggestion or not.
I’m sorry to comment but this step is wrong. The proximity sensor is sticked to the display. I was following this instruction and the sensor was unvelded from the flex cable. Now it’s workless. It’s a fortune that the only problem with the iPhone is that while calling and holding the phone to the ear, the display doesn’t turn off.
I recommend to gently pushing against the transparent plastic enclosure near the sensor and once it’s unsticked, keep pushing against the sensor’s body. In this way the sensor welding doesn’t bear/support any extra load on it.
At least, my iPhone 7G had the sensor sticked to the display. Maybe some day I will replace it (around 20€ - 25€ on ebay)
I won't claim to iFixit nor stop using this website. Whenever I higly recommend to iFixt technitians to revise such kind of “errors”. At least for expensive devices like Apple products.