Has anyone tried to boot Debian Live yet? I can get to boot menu of Debian Live, but when I then start booting I get few messages on screen and screen goes blank and nothing happens. I'm currently testing with debian-live-8.7.1-amd64-xfce-desktop using both USB key and microSD, and neither works.
If I understand you correctly, I ran into the same blank screen issue with Debian Jessie. It was configured to boot to lightdm which launches X11. Unfortunately, as yet, X11 fails to work. There is some information on disabling booting to X11 in this thread: http://www.udoo.org/forum/threads/debian-jessie-linux-os-installation.6819/#post-26060. Are you able to get to the grub menu?
I think I'll give up Debian Live for now and try to install from normal installer-image instead to make this simpler.