I'm using pixhawk 2.1 from profiCNC with here GNSS and I'm not able to detect the external compass.
I have tried the px4 software fmuv2 1.7.0 default and LPE and fmuV3 1.7.3 default with no success at all.
This is not the first time I do calibrate pixhawk 2.1 and I'm pretty used with sensor calibration in QGroundControl.
When using nsh 'sensors status' command line I only see 3 compasses.
If I unplug the GPS, restart pixhawk and retry the same command, only 3 mag sensors are visible.
In stock I do have another HERE GPS which is working fine (4 mag sensors detected)
I have made a teardown and here are the differences :
Working one | No working one
Mag 1 and 3 are populated | Mag 4 is populated
1709 printed on top PCB | 1721 printed on top of PCB
Here are the reference on top of the magnetomer 4 chip
Is this magnetometer sensor not supported yet ?