Advance Wars Cheats (GameBoy Advance)

Press Start + Select + B + A during gameplay.

Open Up New Modes  
Once you complete all the Field Training
missions, you will have access to the War Room, Campaign, Design Maps, and Stats options.

Hold down SELECT as you choose to play the Campaign Mode. You will begin playing in
Advanced Mode. The enemies will be stronger, but you will win more if you complete the
mission.

Hold L + Right + Select when turning on the Game Boy Advance. The delete data option will
appear, which will allow you to restart at the beginning if you want.

Once you beat the Campaign mode, you can go to the battle maps and buy additional CO's.

  layer, you first beat campaign and then go to battle maps where you can buy them.