From ALttP Speedrunning Wiki
Medallion cancel is a minor glitch that causes the magic drain of a medallion to occur but not the spell or its animation.
- Press while moving parallel to a pit at its edge, or into the pit
- Press 1 frame after releasing for a sword spin
- Press on the same frame Link jumps into water
- Press quickhopping works) on the same frame Link jumps a ledge (