The string "1636 - Pokemon Fire Red (U) (Squirrels)" refers to a specific, widely used "dump" (digital copy) of the original Pokémon FireRed Game Boy Advance (GBA) game.
Because these tools were calibrated using the 1636 - USquirrels ROM as a baseline, a massive ecosystem of "ROM Bases" emerged. Hacks like Pokémon Uranium , Pokémon Glazed , and Pokémon Radical Red all owe their existence to the stability of that specific binary file. The file became the "Linux Kernel" of the Pokémon world—a stable base upon which thousands of distinct user-generated experiences were built. To this day, if a newcomer attempts to patch a popular ROM hack onto a different version of FireRed, the community’s response is uniform: "You need the USquirrels version." 1636 pokemon fire red usquirrels