While the main.log only shows the PPA identified in comment #2 there are packages installed from another PPA (with ~oibaf in the version number) and those are likely causing the failure to upgrade. You'll want to reenable the oibaf-ubuntu-graphics-drivers-bionic PPA and then use 'ppa- purge' to remove the PPA and its associated packages.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1915656 Title: can't apply upgrade from 18.4 to 20.4, because there are unindentified sources (but I don't know which are) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1915656/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
