Ok.
i downloaded and flashed version 4.7.3.
It works sometimes, but even if i save the file with it in MIDIOUT mode, if i turn off my gameboy the next time i turn it on it won't be in MIDIOUT mode and sometimes the MIDI modes aren't even options it just stops at KEYBD.
i'm using a dmg and a thursday customs arduinoboy to control channels on a Korg EMX.
i don't know what's going on...