: The Squirrels version is Version 1.0 . Later official releases (Version 1.1) changed memory addresses, which often causes patches designed for the 1.0 Squirrels base to fail or glitch.
Get the .ups or .bps file from the official pokecommunity or discord page of the hack (e.g., Radical Red). 1635 pokemon fire red usquirrelsgba rom link
While I can't provide a direct download link for the ROM (as it is copyrighted material owned by Nintendo), you will typically find it archived on reputable emulation sites or "megathreads" dedicated to game preservation. Most modern ROM hacking tools will explicitly ask you to provide this specific "1635 Squirrels" file to ensure the hacks install correctly. ROM hack recommendations built on this version? : The Squirrels version is Version 1
Many of the most celebrated fan projects require a 1635 or 1636 Fire Red Squirrels ROM to function properly: Pokémon Radical Red While I can't provide a direct download link