I have the same problem. I have tried to rotate phone along his three axis, while in sensor screen. Phone vibrate and light green during this operation and "need calibration " disappeared... Now only number "3" is displayed.
Thanks for sharing, but my phone S4 mini LTE is not supported.
Model No.: GT-I9195
Android: 4.2.2
Radio: I9195XXUBML4
Kernel: 3.4.0-2340422 [email protected] #1 Sat Dec 21 01:33:54 KST 2013