I frequently did the preflight ASI calibration in 4.3 and had no problems. Now in 4.4 it gives the message ‘failed to complete - preflight calibration’ however in the messages tab it says ‘barometer calibration successful’ and it does look like the ASI has actually been calibrated. I dont think I have changed anything else since installing 4.4.
Update -
The first attempt after boot to calibrate airspeed, freezes MP for about 10 seconds and then report ‘failed to calibrate’ however the parameter ARSPD_OFFSET is changed/updated. Any further attempts to calibrate ‘failed to calibrate’ comes back instantly and ARSPD_OFFSET is not updated.