How to get Hardware Decoding working on ROC-RK3328-CC?

Hi,

I’ve recently purchased a ROC-RK3328-CC to evaluate if it could be used as part of our digital signage solution. I’ve chosen it over the Alta and Solitude boards due to it supposedly supporting 4k60 H264 which would be nice. But currently I’m struggling to get any video to play nicely.
I’ve tried Debian, Ubuntu, Raspbian and Armbian. I’ve even tried compiling this fork of ffmpeg thinking that I need special software to access the hardware decoding capabilities.
Does anyone know if there is any way to at least demo smooth video playback? The board would be nice if I could get it to work!