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I was assisting my child in EV3 missions, specifically, the 3rd mission of TRACK3R, the one where the robot has to grab two tires and put them elsewhere.
The mission requires to manipulate the Medium motor at about 90 degree turns: 90 degrees anti-clockwise means "close" and 90 degrees clockwise means "open".
It quickly becomes a hassle to reset the hand to the initial position, from whatever position is was left after the program exited. Forcing the motor to turn until it can't no more is not a solution, because the motor gets stuck, green LEDs on the brick are blinking, and the action block in the software does not advance.