Hi saitama... I'm in the midst of trying to install Armbian on a Netgate SG-1100, which is a similar (?) ARM-based hardware device. It's based on the Espressobin but I think it shares some of the same quirks, including some odd Uboot stuff.
Did you get yours working and running Armbian? TBH I actually would like to get mine running stock BSD of some sort, rather than Linux, but I thought Armbian would be a good test to see if an OS other than PFSense is even viable on the hardware to begin with.