Kubuntu installation while using RTX3090 leads to black screen -> Kubuntu is still running

Question

I have a fresh Kubuntu 20.04 LTS installation on our lab server. Everything in the installation process worked fine. After installation the system boot but i only get a black screen. Imho nouveau crashes bc of the unknown RTX3090, that's what the live system tells me when i try to start it without reduced graphics.

My question is: How can i fix that problem using the live system?

Answer 1

Problem solved.

Nouveau was indeed the problem and it took only a few steps to make the system running.

1. Restart System
2. Press Shift multiple times until you reach the grub menu.

Follow this instructions for fixing Nouveau in grub to start the Kubuntu session.

Finally install the latest Nvidia driver.