as we know as a technician your pal have experienced where the device Redmi Note 4 Mediatek this has been a few screen change was touchscreen still cannot function normally and so is the problem on the power button and volume when viewed from the physical condition of the button no problem.
Well, this usually there is a problem on the hardware side, and for analysis and resolve maybe the picture below can help my friend and of course also its beneficial to all mobile technicians.
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