Just to be sure I have flashed a clean OpenATV 5.1 in both of them. On both of then I can see the bootlogo just after switching it on. I can see on the tv screen the setting options (Video output setup i.e. scart or Hdmi, etc. etc.) on the Dm800se that is ok at the end the booting process, while on the other one I can see the bootlogo on the tv screean when I switch it on, but as soon as the The linux kernel is booting the screen goes away and I got "no HDMI signal" on the tv screen. At the end of the booting process I can see the setup menu on the dm800se display but nothing on the TV.

I do not know how the hdmi signal out of the cpu is handled, but it is strange that i can see the logo at beginning of the booting process and nothing after. If it is a HDMI socket issue or a Cpu issue I should not see anything since the beginning.

Something happens between the bootlogo display and the kernel linux booting that switches the hdmi off. And it seems to me that this has nothing to do with the drivers as well.

One additional thing to point out is that my dm800se use to work fine before but suddenly hdmi went out.