* The Frontier Brains are designed to be post-game content. They are not part of the main storyline and are meant to be challenged after you've finished the main game.
* Gameshark codes primarily modify game data. While some codes could potentially alter encounter rates or unlock areas, they wouldn't directly trigger a battle with the Frontier Brains.
* The Frontier Brains are scripted events. Their appearances and challenges are predetermined, and Gameshark codes wouldn't be able to override that scripting.
Alternatives:
* Complete the main game. This is the only way to access the Battle Frontier and challenge the Brains.
* Use a cheat device to change the game's data. This is a more complex method that could theoretically allow you to "skip" the main game and access the Frontier, but it comes with potential risks and may not be compatible with all versions of the game.
Remember: Using cheat devices can potentially affect your save data and game experience. Use them with caution and backup your save files before attempting any changes.