I tested again. THis time I got the login screen and logged in then the screen got distorted as the display manager would not work correctly. I did "journalctl -b 0" and found also a crash file in var/crash/... I attach both files here.
** Attachment added: "bootlog" https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-amdgpu/+bug/1872452/+attachment/5354081/+files/bootlog -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xserver-xorg-video-amdgpu in Ubuntu. https://bugs.launchpad.net/bugs/1872452 Title: [amdgpu] Boot into black screen without power supply (Kubuntu on AMD / Thinkpad T495) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/kwin/+bug/1872452/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp