Auto land, ekf2 test ratios & flight controller reset

After one or more autonomous takeoff and landing, no matter how smooth the landing, I am often experiencing a situation where the Pixracer flight controller returns one of these errors (and sometimes a position unknown error):


Looking through the code I have not found a way to resolve this other than a full flight controller reset. After the reset the vehicle performs identically to before and is smooth. Accelerometer, gyro and magnetometer are all calibrated fully, as is level horizon. Drone is landing on a smooth, flat and level padded surface indoors.

I am hesitant to set COM_ARM_IMU_ACC, etc to a very high value, after already increasing it past default - for fear of missing a legitimate reason to not arm the vehicle.

Is there any way to reset a vehicles state and ekf2 test ratio variables while running? Ideally through mavlink messages or via mavlink console? Or any other resolution that would facilitate repeated and continued flight testing without dealing with this seemingly arbitrary message.

Drone hw:
Pixracer FMUv4 with 1.8.0 dev (27b2dad)
PX4Flow flow sensor
TFmini range finder
no GPS
custom quadrotor body

Any thoughts or insights would be appreciated!

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Try powering your PX4Flow sensor and TFmini range finder seperately with Pixracer, cause Pixracer is easily get electromagnet interference from other divices. I found this problem with Digi Xbee moudle mounted on Pixracer. the magnetic sensor is seriously disturbed based on its data. But if I power Xbee with a single power module, it is rare to witness this phenomenon.

i think exceeding COM_ARM_EKF_AB can also cause the “PREFLIGHT FAIL: EKF HIGH IMU ACCEL BIAS” message.
We see this High IMU Accel Bias error a lot on our aircraft. We recently found that slowly rotating the aircraft to +/- 90 degrees pitch and roll during ground handling helps the EKF dial in the bias better and seems to clear the error.