A1, at the free-throw line to attempt a free throw: (a) muffs the pass from the official and it rolls forward; or (b) while performing his/her habitual dribbles prior to the release, accidentally allows the ball to deflect off his/her foot into the lane.
In (a), the official should sound the whistle to prevent any violations and then start the free throw procedure again. No free-throw violation should be ruled in this situation. In (b), a free-throw violation shall be called on A1.