Well the device I got technically works but I found the chromebox 3 doesn't support using it.. from the Wiki
Kabylake Chromeboxes were released in the Spring of 2018, and feature a few notable improvements over the previous Haswell/Broadwell models (which are effectively identical). The Kabylake SoC provides a nice speed bump, but more importantly the GPU features full 10-bit HEVC/VP9 decoding, as well as 4Kp60 output (via USB-C DisplayPort alt-mode).
Unfortunately, the GPU in the Kabylake SoC still doesn't natively support HDMI 2.0 output. This means that 4Kp60 output still requires the use of a DisplayPort to HDMI 2.0 adapter (via the USB-C port), and thus a LSPCON (level shifter/protocol converter). The use of a LSPCON means that HD audio bitstreaming almost certainly won't work (due to driver limitations), so one must choose between using the HDMI 1.4 output with HD audio, or the USB-C output with 4K output.
So 4k via usbc but it won't send the audio this way.. I just get the HDMI on AVR flickering and never syncing..
I'll go back to the legacy image for now, and wait until there is a cheapish box that will do 4k and HDR with the device or natively do audio out a different port?..
How do I mark as resolved because it isn't really a bug..