DGX-2 nvidia-release-upgrade from DGX OS 5 to 6

I’m trying to upgrade from OS 5.5.1 to 6 via nvidia-release-upgrade.
During the run I get the following error:

Checking package manager
Reading package lists… Done
Building dependency tree
Reading state information… Done
Ign https://repo.download.nvidia.com/baseos/ubuntu/focal/x86_64 jammy InRelease
Ign https://repo.download.nvidia.com/baseos/ubuntu/focal/x86_64 jammy-updates InRelease
Err https://repo.download.nvidia.com/baseos/ubuntu/focal/x86_64 jammy Release
404 Not Found [IP: 443]
Err https://repo.download.nvidia.com/baseos/ubuntu/focal/x86_64 jammy-updates Release
404 Not Found [IP: 443]

Looks like the URL to the repo is incorrect. focal → jammy
Does anybody know how to fix this?

Check the contents of the ‘xxx.list’ file located in your /etc/apt/ directory.

https://repo.download.nvidia.com/baseos/ubuntu/ focal /x86_64 jammy InRelease

should be

https://repo.download.nvidia.com/baseos/ubuntu/ jammy /x86_64 jammy InRelease
https://repo.download.nvidia.com/baseos/ubuntu/ focal /x86_64 focal

Don’t forget to create a backup before editing the .list file.

After you have made the modifications and confirmed them, run the command $sudo apt update .