The .SRL is from Mario Kart DS (USA) (NDS) (Virtual Console), a Wii U software. Here is a patch to Mario Kart DS (USA), an NDS software. I tried ndstool on the ROM, and one of the things it tells me is: Code: 0x6C Secure area CRC 0x3B22 (OK, mask ROM) does anybody now what a "mask" ROM is? and how to convert it into a decrypted ROM? Retrogamefan has contributed some info: Does anybody you know what the extra data is?