[ditttoo]

Seems the distinguishing factor is whether the backboard belongs to A or B.

Case 4.4.5 A1 atytempts a pass (said it was not a try, so it must be a pass) to A2 during pressing action in A's backcourt. The ball hits B's backboard and deflects directly back to A1 who catches the ball and a) passes the ball to A2; or b) starts a dribble. RULING: The pass against B's backboard was the start of a dribble which ended when A1 caught the ball. In a) the passis legal action, in b) it is a violation for a second dribblem (9-5).

Now let's see what Rule 4.4.5 states, "A ball which touches the front faces or edges of the backboard is treated the same as touching the floor inbounds, except that when the ball touches the thrower's backboard it does not constitute a part of a dribble.

So if A1 slings it off his own backboard he can continue to do whatever he wants.