This is interesting, there is a thread about the exact opposite, only the c stick and zl zr work, nothing else, so what do all the other inputs go through? Was this to maintain compatibility with original 3DS software?
Just got a console with these same issues, did anyone figure out if this was a solder problem? I have a donor 2DS board can I take the microcontroller from it and solder it to the nn3ds as a test?