Ubuntu 20.04 upgraded the kernel from 5.4.x to 5.8.0 in 20.04.1. This broke my audio, ethernet and wifi devices. Problem root caused to not having all the modules installed:

See also this post which points out how to back out of the 5.8 kernel if you need to do that (essentially just reverse the above list of commands, haven't tried yet)

• To check your running kernel, uname -r
• To bring up the grub boot screen with old kernel logins, hit ESC as BIOS finishes

System76 Install Ubuntu Guide - after installing ubuntu as usual, fetch the system76 ppa and install their drivers. See the guide for the latest details, but the relevant parts are:

Oryx Pro Schortcuts

• Toggle WebCam: FN & F10
• Toggle Backlighting Colour: FN & '/' (on the numeric keypad)
• Toggle Keyboard Brightness: FN & '+', FN & '-' (on the numeric keypad)

Had to resize swap/root encrypted logical volumes.

TRI doesn't use the desktop network managers. Configure network from /etc/netplan/01-netcfg.yaml:

You might also wish to comment out everything in  /etc/netplan/01-network-manager-all.yaml which allows (I think) Ubuntu's network manager to configure it as well - in my case it was giving it a second, dhcp provided address. Cool, but ultimately very confusing when most utilities don't think an interface can get two different addresses. ifconfig was saying one thing, avahi another.