A base ROM refers to the original, unmodified version of a Pokémon game, containing the complete and unaltered data as released by the developers. In Pokémon ROM hacking, a base ROM serves as the starting point for creating custom modifications, such as new storylines, features, or graphical updates. For instance, using a base ROM of “Pokémon Emerald” allows hackers to build unique games while maintaining the core mechanics of the original.

It’s crucial to use a proper base ROM when patching or creating a ROM hack to ensure compatibility and a smooth gaming experience. A clean base ensures that the custom modifications work as intended, avoiding potential errors during gameplay.