I’m curious. why are you looking at Firefly-RK3399? (I don’t have any experience with the RK3399.) It seems pretty expensive though just to run openHAB. Like @Thedannymullen, I also use a PI (3B), and I’m quite satisfied using it to manage a combined Insteon and ZWave network. The PI also has the advantage or pretty broad support here in the openHAB community and elsewhere on the Internet.
If your good with linux and understand how everything is structured then support won’t be a big deal. It’s always good to have someone use OH on a new device and share with the community. Unfortunately, most people starting out with OH have very little linux experience and sticking to a common platform is best.
I was looking at the RK3399 as it had greater specs, upgradeable RAM and could boot Ubuntu 16.04. My only concern with the PI is related to performance. I use the IPcam binding to get snapshots from 4 cameras around my house which is quite taxing on the system.
@H102 Fair point, I have a PI at home so is worth setting up as a proof of concept atleast. My main requirements are the ability to connect via 4G and create a wifi hotspot. Which the PI could potentially achieve with something like this