Another way, if there are problems doing it directly, is to install 12.04 as a minimal installation, then upgrade it to 14.04. As a reference point, I recently upgraded my 12.04 installation (with full desktop, and plenty of other applications) to 14.04 with no problems specific to the UDOO. So this is a valid alternative for the (unusual) situation that the direct 14.04 installation doesn't work. There are problems with the distribution upgrade, but I've found the same issues with my PS3, and with my Ultra Sparc devices too. The problem being that significant parts of unity are missing (uninstalled) following the upgrade, and have to be installed manually. There is a package that conflicts with the automatic upgrade, and leaves the unity installation half complete. For both my PS3 and Ultra Sparc devices, I could fix this later from a command line. For the UDOO, I couldn't fix Unity before I ran out of patience (3 hours). I ended up just installing xubuntu (LXDE) desktop which, in any case, works much better.
