My board also has problems with the HDMI. In some cases I do get a view, mostly not. I think its a timing syncing issue. My lg monitor seems to work sometimes but my philips monitor does never works. Just tried my Samsung television and that seems to works for me. Sony tv also works. My sony tv pops 720p so probably my monitors do not support this. Have you tried a television already?
I am using the old debia lite image.