I have some trouble with my Lime 2.
My original setup:
Armbian 5.38 +4.14.18-sunxi
software installed: Pihole V3.0 with dnsmasq dhcp enabled.
SD : a fresh Samsung Micro SDHC 32GB EVO
power-supply : a 5V power-supply adaptor
After [1~4] days the my board disapear of my network.
With dnsmasq dhcp server disabled, there are no problème.
My guess: their are some troubles between the dhcp and Armbian.
Indeed in tried to setup a isc-dhcp-server to remplace the Pihole dhcp without success. (Same behaviour)
You could see my search on Pihole forum here
After my vacation, i will test the olimex's image with pihole.
However this return to Jessi and a 3.4 sunxi kernel, doesn't enjoy me.