I received this today and attempted to load Debian 9 for dual monitor and original Debian 9, Ubuntu Server 20.04 and 18.04, as well as Armbian (most current). All failed to output any display via the micro HDMI. The one software load that did work for video halted the startup process every time I attempted it. I am new to Linux, but have built computers before.
Installing via Mac OS: Format type MS-DOS (FAT) with GUID Partition
Booting from eMMC 64 GB drive
I was unable to get Etcher working on my Ubuntu laptop, was an attempt to try a different OS built boot drive. I plan to attempt with Windows tomorrow…
Thank you for any support in advance!
Update: The Ubuntu Server 18.04, which is not listed for the RockPi 4C is the only one that outputted video.