You cannot run a .gba file on its own. You need an emulator. The best options for an Indigo League playthrough are:
Tools like Lunar IPS are used to apply the "Indigo League" modifications to the clean FireRed file. Pokemon Indigo League Game Gba Rom
Note: We do not host ROMs directly, but searching for "Pokémon FireRed (U) (V1.1).gba" will yield the correct, clean dump. You cannot run a
: You start as Ash in Pallet Town, sleep late, and get Pikachu. You follow the specific path from the show, including meeting Misty after her bike is destroyed and releasing Butterfree. Pokemon Indigo League Game Gba Rom