Of course i have no working xorg with that setup.
Hm. Let me thinkā¦ I pulled the pyra.dtb from the EVM - but with BOE panel. So it might be the one with the BOE driver which fails to init the DSS if no panel is connected.
Please try the attached .dtb file (which uses the panel-mipi-debug driver that works with no panel connected).
Seems the problem was more to do with it choosing lcd as the default output instead of hdmi, since xorg was opening a 720x1280 screen.
And after a bit of kernel option fighting, adding omapdss.def_disp=hdmi does make it work :)
I'll still have to check if this is any more stable.