Have the Game Boy Advance game Super Robot Taisen: Original Generation in the cartridge slot. Start a new game or load a saved game file to get the OG1 Choker that increases your SP by 100.
Have the Game Boy Advance game Super Robot Taisen: Original Generation 2 in the cartridge slot. Start a new game or load a saved game file to get the OG2 Pendant that increases your HP by 250.
Successfully complete the game, and save when prompted. Load your cleared saved game file to start a new game with your previously earned money and items.