Question GoPro Hero 5 Water damage

[orangeme]

Hi, so I've had my gopro in sea water, it stopped working after that, I've tried to turn it on straight away, it turned on for a bit without the display, I've left it for a while (almost 4-5 months) and tried to turn it on today again, it turned on fully, without the display screen but then the display screen turned on also (fully operational), it I tried to turn it off but the button didn't seem to be working, is this the motherboard? or something else?

 

[hang-the-9]

With liquid damage it could be a lot of things, no way to to tell unless you take it apart and start testing components and connections.