Servo 4 Locked and not movable

I just recieved a new uARM and ran the calibration code here:

The calibration seemed to go smoothly, It ran, then it asked me to position the arm (servo 1 to 3: 45, 130 and 20 degree) and then it said calibration complete. After that Servo 4 (the servo at the end of the uArm) is completely locked and cannot be moved manually. I tried using code to detach the servo and it did not help. I also tried recalibrating it which I could not complete because I could not move it to the final position due to servo 4 being locked.

hi @mike3, I submit a new version v.1.6.1 fix this issue.