Welcome to Armbian.
I would suggest you read:
https://forum.armbian.com/topic/16976-status-of-armbian-on-tv-boxes-please-read-first
and
https://forum.armbian.com/topic/17106-installation-instructions-for-tv-boxes-with-amlogic-cpus
As for your question, I would recommend using a stable build not a development build. Also if that doesn't work, try a server (CLI) build. I've been seeing reports in the forums about hdmi not working across different builds when running desktop builds.
