I am using a Samsung Galaxy S4 mini with Cyanogenmod (11) and want to calibrate the compass / magnetic sensors.
With the stock rom this was possible by "dialing" *#0*#
. This is however not implemented in Cyanogenmod.
How can I calibrate?
Give this a go:
Try to stay away from magnetic fields as far as you can
Open GPS Essentials and tap on compass (calibration will not work when the compass is not showing)
Put the phone on a flat surface with the display pointing up
Move the phone slowly, 5 seconds per full rotation is ok
Rotate the phone three full cycles around the axis pointing upward
Rotate the phone three full cycles around the axis pointing away from you
Rotate the phone three full cycles around the axis pointing right
The direction of rotation doesn't matter
This should fix your problem.