This is the holy grail. In version 1.0, you can duplicate any held item—including Master Balls and Rare Candies. How it works: Go to the Battle Resort. Enter the small house left of the Pokémon Center. Talk to the girl who offers to trade you a Pokémon. Offer a Pokémon holding the item you want to clone. When she asks to see your Pokédex, press B to cancel. The Pokémon will still be in your party, but the item will also be in your bag. Repeat for infinite Rare Candies. Note: Patched in 1.1+, so treasure your 1.0 copy.
Later updates fixed these “cheats” but also added minor stability improvements. If you have a 1.0 cartridge, consider yourself lucky. You own a piece of Pokémon history that lets you bend the rules of Hoenn. For everyone else, you can still enjoy these tricks by deleting update data from system settings—but that only works if your cartridge is 1.0. Pokemon Omega Ruby Cheats 1.0
Have you found any other version 1.0 secrets? Share them in the comments below. This is the holy grail