After some experiments and meditation on the process I have found the reason for the installation error in my case.
Somehow -- most likely due to my mistake -- the EFI system partition (ESP) switched to being a logical partition. However, UEFI needs it to be a primary partition. Since I've already broken other OS installations on the machine, I have recreated ESP as a primary partition and Ubuntu 20.04 installed fine after that. I guess it may be a good idea to add a warning to the partition dialog if such situation is detected. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1872212 Title: grub-install: Operation not permitted To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2-signed/+bug/1872212/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
