As I have one of these Flytrex Core V2 GPS flight logger modules lying about, thought it woudl be a idea to installed it into the M5.
On the board above the sonar inside M5 where camera is plugged in are nicely labelled GPS pads.
All you need to connect the skytrex core 2 is to solder 4 wires onto the pins , gnd , 5v , gps tx and gps rx and you are set to go.
I think from memory I might have got the gps tx and rx wires (green and white) around the wrong way the first time, so if you follow this and it dont work then swap those 2 wires, the others wires are correct.
The module then fits inside area where battery wires come out and is enough room to leave it in there and pull it out when you need to read the logs from the sd card.
Video with overlay in next post.
Works fine and might also end up trying the Flytrex on the S6.