Technically, this doesn't have to do with the NB4...but, I just thought I'd mention it, due to the similarity. Not sure how many in here know what an EDL (electronic driver's log) is...but, they are found on commercial vehicles for companies that have been approved by the DOT to switch from paper logs. Anyway, the company I drove for uses units from Saucon. While the newer units appear to work without any problems, the older units tend to have this exact same "black screen" problem...and, the 'solution' is also the same ("reboot", and the problem doesn't happen again for at least a couple weeks). As the same software updates are pushed out to the old and new units, alike, that would lead me to believe that the problem is not software related...it would have to either be a hardware problem, or a BIOS problem.

For those having the "black screen" problem with the NB4, are yours one of the more-recently-manufactured units, or one of the older-manufactured units? If this problem is affecting only the older units, it could be similar to the Saucon problem, Which would lead me to believe that, at some point, FlySky either switched certain components to more updated components and/or the BIOS (or equivalent of BIOS) is different than the BIOS in newer units. This is just a theory...but, it could be an 'accurate' one.