"Mode is not supported" after playing with settings, black screen

I recently got my N2 and because it didn’t play all my files as it should, I have been playing a little with settings. It all got wrong when I activated the SDR to HDR (I think). The result is that I now can’t see anything after the reboot. The screen says “mode is not supported” “resolution is not supported” “change the resolution of the external device”.
So, how can I change this when I don’t see anything?
Is it anyway to reset N2 back to default?
Or could anyone post some pictures of menus, picture by picture so I maybe can change it back in blind?
Also I am a complete n00b at this :slight_smile: