If somebody gets the same problem as me:
All my game worked fine except Mario RPG. Here's a workaround I found on Hyperkin's facebook page:
1. Boot any game
2. Press and hold the reset button
3. Remove the game, and place Mario RPG
4. Release the reset button, the game will now boot.
It also have to do this for Kirby's Dreamland 3 and Kirby Super Star.
It also have to do this for Kirby's Dreamland 3 and Kirby Super Star.