1. Get a copy of DietPi install for NE2
2. Unzip the file and make a Linux boot micro-SD card using Win32DiskImager
3. There is a configuration file that is created which I think is called Config.txt or something like that. It is in the root directory.
4. Go to the part where there are IP addresses starting with 192.XXX.XXX.XXX. If you have such a range of IP addresses in your home network, you don't need to make a change. Otherwise, set the numbers to what you use at home. I also set the Static-IP field to 1/enable above this section.
5. Save the above file, eject the micro-SD and put it in the NEO2. Turn it on.
6. Shortly after start-up, you should see a blinking green light. If you don't see this, something bad has happened.
7. Wait 2 to 4 minutes for it to fully boot up. Ping its IP address to see if it is alive.
8. SSH into NE2 using the IP address and root as the user. Password is dietpi. I didn't have luck using Windows ssh so resorted to using Putty which works better anyway.
9. Once you log in, it will ask you some questions and then will go through upgrading a bunch of packages. Use the tab to jump from one option to another. Note that the mouse does not work. Only keyboard does.
10. After a 10 to 15 minutes, dietpi should be ready to go. Go into its configuration utility and select RoonBridge to install. After a few minutes of running this you are done.
11. Roon should see the NEO2 as is even without a DAC connected. If it doesn't, something got screwed up again.
12. Connect your DAC and it should show up in Roon.
You will probably struggle some in the menus but the above is the high level sequence.