Had the same error message installing Ubuntu 20.04.1. Following Alexei Lozovsky's advice above, I made my EFI partition the first partition on the disk, and also made it a primary partition as opposed to a Logical partition within an extended partition, and the installation completed successfully. (My disk is still MBR partitioned, but I am using UEFI).
-- 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
