You can use the 2 controller method to unlock this jam challenge. all you got to do is go to into a "Play Now Game." have the settings on 5min, easy with no shot clock. I picked the Lakers V.s the Kings and I was Kobe Bryant. U want to shoot the ball at half court and quickly run to the ball and press the hell out Y button. You wont be limited to one shot only, if your lucky you can get a few tries before it finally goes in. I made talley marks just to make sure and I got like 7 in the first half, 17 total. I know this can be hard at first, but keep trying and believe.