I had issues with my usb port on mine MX4 PRO. Often wasn’t charging and I would have to tweak with the cable of the charger to be able to charge and even than often it would discharge more than charge.
I live in the Netherlands, so I ordered a new USB charging dock port from China, I replaced it and now I can charge normal but it seems I lost my 3G/4G connectivity. My phone is now only able to detect 2G networks.

I was wondering if the board is somehow connected with the modem or the antenna. Because there is a cable (u can see it on the image below) coming from the top left part of the phone that connects to the board and I have a feeling that is related with it.

I would appreciate if someone could help me out. Thanks!