Obtaining modified versions of Game Boy Advance Pokmon games involves acquiring ROM files that have been altered from their original state. These modifications often include changes to gameplay mechanics, storylines, available Pokmon, and even graphical elements. As an example, one might find a version of Pokmon FireRed where all Pokmon are available from the start, or one with a completely original region and story.
The popularity of these modified games stems from a desire for novel experiences within the established Pokmon universe. They offer a way to replay familiar games with fresh challenges and content, extending the lifespan and enjoyment of classic titles. Historically, the creation and distribution of these modifications have been a grassroots effort, driven by dedicated fans with programming and game design skills.