Rock64: MAC Address is NOT Unique!

[as365n4]

You need to spoof the MAC address when you have more than one on your network.
It seems the MAC address is not physically burned onto a chip or something, but is created by the Operating System and changes with Linux flavour (Arch is different than Debian for instance)

create /etc/systemd/network/00-default.link like below

Code:

[Match]
MACAddress=da:19:c8:7a:6d:f4 <--- whatever your original address is

[Link]
MACAddress=da:19:c8:7a:6d:f5 <--- your desired address
NamePolicy=kernel database onboard slot path

This will overwrite the system settings at each boot and works fine on Arch and Debian.