The Jetson and Driver package instructions for flash are correct, it’s the ‘sudo do-release-upgrade’ which will break things. I think some people have experimented with this, but mostly you can expect an upgrade through non-NVIDIA tools to break the system (or at least to not guarantee it works…Ubuntu servers do not have knowledge of direct hardware accelerated access of a Jetson). This is the URL for things to download and flash:
You can flash directly from command line using the driver package and sample rootfs, or you can use JetPack (which serves as a front end to the driver+rootfs along with other package and configuration setup).
The edid search command listed in the prior post will answer what configuration data the Jetson actually received, but it won’t matter if the NVIDIA drivers were overwritten by the Nouveau drivers.