rev, those who are citing 9.3.e are missing that the backboard must be over a non-playable area for that to apply.
Since, in the instance of the backboard near the end-line, it seems as though it would be over a playable area, the ball would be dead because we are going to make a judgment as to whether or not the ball could have been played had the vertical backboard NOT been there.
If the ball is headed for down-town Timbuktu, then when we blow the whistle, the play is dead and the ball is out-of-bounds. On the other hand, if the ball is looping in such a way that, if the vertical backboard had not been there, a player could have had a chance to make a play on the ball, then we will have a whistle killing the play and a judgment replay awarded.