That is just what they said, one of my friend mount a game to sky3ds and put it to 3ds fw 1.0, and no thing happen, if that is a real cartridge, it's should ask to update fw right? and i dont know if sky3ds could run devmenu or not, any tries? My friend sold that sky3ds away so that i could check it myself but sky3ds could run cubicninja, then Sky 3ds support hombrew too.
Wait. So..
Your friend's 3DS was at 1.X FW and Sky3DS didn't work on it?