Chosen Solution
i recently picked up an iphone 7 plus that appeared to be in good condition. upon setup i realized that it could not see my wifi. tested wifi with my old 6s and it was working fine. set the 7 plus on the router and it would see and connect to wifi. figured it was an antenna problem after some reading online. ordered the wifi diversity antenna that goes on the loud speaker, turns out that wasnt the problem. i than learned that there was a second antenna in the top left corner that consisted of a black plastic cover. so i removed this black plastic piece and upon inspection i came to realize that something on the board had burned. what would be the cause of this im going to guess that this board is junk now since the wifi doesnt work properly but looking for another opinion. i attached some pictures of the burned area .
Update (06/29/2019) Liquid damage seems kind of odd for an iPhone 7 Plus because I read they are waterproof for the most part.
There is just one option here, charred components have to be removed and replaced and then damage reassessed. Skills and tools are needed as well as a professional in microsoldering. I wouldn’t be surprised the burn was caused by liquid damage.
