As far as we know these issue are all caused by the install_devices debconf entry becoming invalid due to hardware configuration changes, and then a subsequent upgrade in non-interactive mode failing due to this.
Interactive upgrade or re-installation will simply prompt to specify the new install device path. A solution to make this nicer in the future is to use UUID based install_devices tracking, but I consider this a new a feature instead, and lowering priority to Medium ** Changed in: grub2 (Ubuntu) Importance: Critical => Medium -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1940723 Title: GRUB (re)installation failing due to stale grub-{pc,efi}/install_devices To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1940723/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs