The Helmet, Boots, and some luck are required for this trick. You usually get the Upgraded X-Buster from Zero, but you can get it much earlier than that. In the Flaming Mammoth Stage, there is a part where mine workers throw picks at you, and where you get the heart and sub-tank. Before you enter there, there is a small location that you can break with your helmet just at the entrance of that room. With luck, you can reach the place with your boots and break the blocks with your helmet. Then, climb straight up to get it.