Thanks, sfx2000. But I'd already "disabled" IPv6 using that method.
On my first Armbian setup attempts, no matter what I did, my system never got an IPv4 address.
It only ever had an IPv6 (despite my network being IPv4.)
Eventually I stumbled on that `armbian-config` option.
Once "disabled" it allowed the system to get an IPv4. But despite what it says, it didn't "disable" IPv6 system wide.
Tools like `ip addr` and `ifconfig` showed it still had IPv6 active.