Just some notes.
Got my hands on a BananaPi Model A and started to try out some images. First I got the Gentoo image, wrote it to SD card with dd and resized the partition to use the entire SD card using gparted.
Network failed to start on boot. Not sure why but changing
/etc/rc.conf and enable hotplug resolved the issue:
... # This allows all services to be hotplugged rc_hotplug="*" ...