SFC and SMC files are usually identical. It’s just a different choice in file extension. “SMC” comes from Super MagiCom, a floppy-based cart copying device for

SFC and SMC files are usually identical. It’s just a different choice in file extension. “SMC” comes from Super MagiCom, a floppy-based cart copying device for backup/piracy. The original .smc files produced by the device contained a 512 byte header. Since it’s pretty easy to detect and ignore most emulators do. If not, it’s easily removed. Because .smc is in reference to effectively a piracy device, the new preferred file extension is .sfc and has been for a while now. (In case it is not obvious, the file format is nominally just a raw dump of the ROM on the cartridge with no added headers.) (Note 2: if you are looking for a way to run homebrew/patches/etc on a real SNES/SFC nowadays, sd2snes is probably the absolute best option.)