@john-l-clark Here are the exact key sequences I used to build this driver on a brand now Ubuntu 20.04 image in my virtual lab.
sudo su -
apt update
apt upgrade
apt-get install wget git build-essentials -y
reboot
git clone https://github.com/acooks/tn40xx-driver
cd tn40xx-driver
make
sudo make install
modprobe tn40xx
tail /var/log/syslog
lsmod | grep tn40xx
When you review syslog look for errors regarding this network adapter. Ignore the one about the tainted kernel.
If everything goes ok then you will need to create a startup file in /etc/modules.d so that this network driver loads on every boot up. Once its there then reboot and it should pick up an IP address, if not make sure its listed with the lsmod command like above. For ubuntu you may have to use the network manager to assign an IP address for it. I’m not a big ubuntu user, so I’m just guessing. But it took me longer to install ubuntu than it did for me to build this network kernel driver. Keep the installer files because when you upgrade your linux kernel you will need to recompile this network adapter driver.