Hi,
I've similar issues with the N8 Pro than the guys with Hi-def addon and a N8 Pro.
I'm getting most of the time a grey screen and if I'm getting an menu, I've no issues to play my games. I'm using an Famicom AV with a new 9V MeanWell power supply. I've also installed a NESRGB and a NESRGB-IGR. I'm also tried to reset the console, if I'm getting the grey screen and re-insert the SD card with no success.
I've also tried other SD cards (Sandisk 8GB with Fat32 and a Samsung Evo 64GB with Fat32) both with the same grey screen.
I've installed the latest Firmware 2.06 on the SD card.
It looks like the SD card initiation process is to fast and the rest of the modul is not ready, maybe a power consumption issue.
I've also tried an other N8 Pro from a friend of mine with the same behavior.
I've no issues with original cartridges or connect issues.
Do you've any ideas?
Thanks & Br