Most ROM hacking tools (like or specialized SonMapEd tools) do not work on the combined 4MB file directly; they require the original 2MB chunks.
& Knuckles , typically sourced from the SEGA Mega Drive & Genesis Classics collection on Steam. It is most commonly used as the required base file for , a fan-made remastered version of the game. Locating the File sonicknuckleswsonic3bin file work
The file is the specific ROM file for Sonic 3 & Knuckles Most ROM hacking tools (like or specialized SonMapEd