Well, as someone who's background is marketing rather than code, the first steps to effective marketing are generally figuring out who your audience is, what they're looking for and where already they are currently placing their attention.
I'm not a firmware coder, or even a coder at all, so these are not easy things for me to answer. (Compsci students? Interesting challenges? Hacker news?) Usually I'd start by asking someone who matches what I'm looking for though.
@lupyuen @PINE64
Hmmm... I wonder where one would find firmware devs to interest? It seems like a rather niche and specific skillset, even if the possible use for the devices is widespread.