@austin-c , The GPS driver is built for SLPI as well as APPS PROC, so you could connect it to a apps-proc UART and start the driver on the apps proc side of PX4.
This was done on RB5 : https://docs.modalai.com/Qualcomm-Flight-RB5-linux-user-guide/
https://docs.modalai.com/voxl2-linux-user-guide/
Regarding magnetometer, just like with the GPS driver, you should be able to enable the mag driver to build for apps proc. Since the apps proc i2c uses standard posix interface, it should just work. However, i don't think we have ever tried it.
Alex
