Is this related to the problem? Haven't attempted this solution yet, but I am on a 2011 Macbook Pro running Ubuntu 20.04 experiencing the same issue.
https://askubuntu.com/questions/1279602/ubuntu-20-04-failed-to-set- moklistrt-invallid-parameter -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1867092 Title: Failed to set MokListRT: Invalid Parameter To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1867092/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs