S8 mobile phone has been unable to locate for a long time. What should I do?

I don't know what navigation software you use. First look at the settings in the software. Is there a port setting? Port 4 is generally selected. Because you can locate online, you can disconnect from the network and see if you can navigate. If not, there may be something wrong with the gps module. You can use it before brushing, but not after brushing. Maybe there is something wrong with the rom you brushed. If there is nothing wrong with the rom, your baseband may not match your rom, and you need to refresh the baseband. The above are basically possibilities, I hope I can help you. '