This only works on the black and white version of the game
Go to the spot on the first screenshot, near where you get the sword. Now, go one screen to the east and then do the Screen warping glitch to the east so you're about in the spot in the second screenshot. Now, go back to the west to reset the sword screen. Screen Warp to the east again and you should have a sword there, which becomes the level 0 shield (which can be used)!
Submitted by: Kenjoki-Ikari