It's not hard. The screws are held on by c-clips on the back of the cover. Get pair of needle nose jewelers pliers and squeeze the clips off the screws. They'll pop right off. If you want to leave the screws in for aesthetics, you can remove the bottom of the 3DS, take apart the shoulder button assembly, and remove the square screw receivers. Those will remove what the screws use to hold them in place.