The Olfi requires a specific 10 pin setup for the microphone to work.
The setup is as follows:
GoPro do not utilise the same mic setup as us, therefore no GoPro compatible mic will work as is. The USB connection would need to be re-wired to make it compatible. Pins 8 and 9 control the switch over to the external mic capability (see pic) – I believe GoPro Mic pins may attach to pins 3,4 and 5 (including GND)but don’t quote me on that!
If you wanted to attach an external mic using a 3.5mm jack connection so that you can use any microphone you like that has a 3.5mm jack, this is the only listing that i know will work as we utilise the same pin setup. Any mic advertised which says it will work with a GoPro will not work with the Olfi.