I think the issue may be that you removed the oibaf (and other) PPA(s) from your package list before using ppa-purge. Try re-adding it and then running ppa-purge. ppa-purge will remove the PPA from your sources after reverting packages, so you do not have to do that manually.
sudo add-apt-repository ppa:oibaf/graphics-drivers sudo ppa-purge ppa:oibaf/graphics-drivers -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1896380 Title: An unresolvable problem occurred while calculating the upgrade. 18.04 to 20.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1896380/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
