(Can't see dates and times for posts, so dunno if problem solved by now)
Had you removed the SD card at all to make some changes before it started not working?
Just a couple days ago, I put in my SD card, started up Gecko OS, hoping for some Brawl Minus. The menu didn't load. Tried playing, characters weren't hacked, and the stages weren't different. Custom music was also back to normal. But the codes loaded perfectly (Default Settings Modifier, Hybrid Air Dodge, etc)
And then I took it out, tried to edit some files, and noticed the SD card was locked. Maybe solves the problem? I dunno about Riivolution, but anyways, that's my little two cents.