Will try and report. It is hard to say if something solves it, since it may fail after 10 or 20 boots, or 100... X is always run with the username 'linaro' or depends on the ubuntu user?
The problem I had was screen blanking in X. Since X is run with the username 'linaro', I put the following lines in a startup script (/etc/rc.local) and it seems to do the trick:su linaro -c "xset -display :0 -dpms"su linaro -c "xset -display :0 s off"Does this help in any way?