I can calibrate it successfully in MobileUncleTools by going to 'Engineer Mode -> Engineer Mode (MTK) -> PSensor' and perform the calibration procedure. The proximity sensor will then work as expected until a reboot after which it is back to the same problem again. So I have to perform this recalibration after every reboot.
So what I would like to know, Firstly, is if anybody knows why the calibration in MobileUncleTools is not saved and does anybody know where the calibration settings should be saved to so that I can manually alter the settings. I have looked through all the system config files and I cannot find anything relevant.
Secondly, does anyone know of any other method of calibrating the sensor that would survive a reboot.