Ok I posted this on 12volt.com site a month or so ago, but no luck, so let me try here.

I have an N1 (w/50MT disk)and everything seemed to be working fine until I bought and downgraded to the 40MT disk, believe it still worked fine for a week or so and than pretty much everything that was coming off the brain stopped working( i.e. radio, IP bus cable, and Nav) everything still works great on the unit as far as dvd's and cd's but nothing that comes off the brain. I have since bought a N2 and swapped head units to troubleshoot and everything worked great, so it's something in the head unit that's causing the problem. I have upgraded back up to the 50MT and have just upgraded to 60MT to see if that would work. Still nothing. Anyone have any ideas as to what would cause this? Very strange since everything on the headunit is working great, just the inputs on the brain are affected..