Only my axes (x, y, z) that do not return to zero, in the photo it shows them too. (and I think my positionhold is not perfect so the axes have a little problem with zeroing)
But, I will try with the 3m usb cable.
These axes only compare "onboard" mag with "aux" mag, they are mainly to help you correct for aux mag mounting angles not correct, and even for some small mag fields in the model. You should ignore them because you are using aux mag only and know there could be problems with onboard mag calibration.
I posted a photo showing the status of the compass, onboard (5.5%) and auxmag (0.4%)
a very big difference between them.
These numbers are entirely calculated from the measured strength of the mag field and have nothing to do with direction (which is the important part for us). This is because the FC just doesn't know where north is except by looking at the mag/compass. Using the mag/compass to define where north is, it obviously doesn't make sense to score the mag/compass accuracy based on where it thinks north is.
The next best thing is field strength. Your onboard mag field strength measurement is 5.5% off of what it is known that it should be, but your "aux mag" field strength is only off by 0.4%. Use the aux mag and forget about the onboard mag.