After ongoing stability problems with (L)Ubuntu I switched to Bananian 2 weeks ago and the BPI is now running stable (as expected). Switching power supply and SD card did not help in contrast to the change to Bananian.
So, please try Bananian first, since it seems to better match the hardware (kernel, bananian-config, bananian-update) than Lubuntu and Raspbian.
With the documentation from my (L)Ubuntu setup it was a question of hours to migrate to Bananian.
Ubuntu Firewall was replaced by a standard setup with Netfilter/ip(6)tables configured into iptables-persistent.
backupninja with duplicity method is still responsible for the daily backup.
This device is still providing the jump server on IPv6, Wake-on-LAN for the VDR Appliance, dnsmasq for the ULA subnet, SMTP Reminders, … one of the most important devices in the LAN.