Recently I bought a nanopi fire 3 and installed armbian without any issue (Armbian_5.91_Nanopifire3_Debian_buster_next_4.14.133). The first thing I did was to connect the nanopi to my ADSL router in order to complete the basic configuration. Everything worked fine.
Then I connected the nanopi to an Edimax gigabit ethernet switch and here is where the network problems appeared. The ethernet connection was too slow, with ping times of more than 1000ms, and an unstable behavior that made it almost impossible to connect via ssh.
64 bytes from 192.168.22.12: icmp_seq=1 ttl=64 time=1004 ms
64 bytes from 192.168.22.12: icmp_seq=2 ttl=64 time=1025 ms
64 bytes from 192.168.22.12: icmp_seq=3 ttl=64 time=1001 ms
64 bytes from 192.168.22.12: icmp_seq=4 ttl=64 time=1002 ms
After many reconfigurations and reinstalls, I tried forcing the ethernet interface to work at 100Mbps, and it solved the network slugginess and unstability.
ethtool -s eth0 speed 100 autoneg off
Other devices connected to the same switch work fine at 1Gbps.
Although with this workaround I can work for now, I still want to use my nanopi at full speed if possible. Anybody has any idea of how can I solve it?