Setting up TNC-Pi9k6 - Raspberry Pi Hat with Pi 4

Notes from my setup that others might find helpful:

Using latest build of raspbian

Ran os updates:
sudo apt update; sudo apt upgrade

Ran firmware update:
sudo rpi-update

Detecting the TNC and running getparams first time:

Following the manual here as it's for this particular hardware: https://www.wvcarc.com/p/tnc-96k-resources.html
And additional help from this manual since it has much more information: http://www.tnc-x.com/TNCPi.pdf

Serial Port - it should be on /dev/serial0. To enable it, do:
sudo raspi-config
Select option 5 for Interfacing options
Select option 6 for Serial
Say "no" to the login shell question.
Say "yes" to serialport hardware question.
Reboot
Now you should see output when you do "pitnc_getparams /dev/serial0 0"

Software Setup

Following this guide for software setup: https://dl1gkk.com/setup-raspberry-pi-for-ham-radio/
Skipped the direwolf stuff for now since I'm using the TNC