Ignore that ubuntu 12.04 LTS support will end in few weeks, do not dist-upgrade to 14.04.
You get many problems with libs, which can be fixed... But you cant fixed, that 14.04 dont support "udev" and if you
uninstall udev and try install again... Thaaan your controllboard will no more boot up
My story, because this i use Rasp as controller... The stock-controller powered now only the fans
If i got time, i will try to rescure with SD card. Somebody know this? -> For bootup with SD, must the jumper set to anything? Because
plug in&boot from SD with some ARM-dists dont work.
Once i was able to run it off a PI ,I went with Ubuntu 16 for the reason you stated above . I use any PI not just a RPI ..... so the pins won't really matter much sense they seem to be about the same on all PI types not just RPI, if you use USB DONGLEs not the on board GPO's on the PI's .
Thanks for that water cooling guide i haven't got around to doing, been to busy with real life, like health issue etc ...