If it were me, I'd definitely place a jumper on those two contacts, then apply power to the NVR while a video screen is attached. Do be certain to allow several minutes for it to reset to default firmware, at least 3 to 5 minutes. After that, remove power, remove the jumper, and re-apply power.
Unfortunately it doesn't work on my NVR 4208.. Do you have any clue ? There is yellow battery that I can't remove, do you think the problem comes from there ?
