Dell XPS 13 9343 here too, running Ubuntu 18.04.1 with 4.15.0-23-generic. However, I do not use the same method as @mes2k for BIOS updates. I just boot into Windows to install the .exe... Therefore I have nothing under /boot/efi that could be causing it...
➜ ~ sudo dpkg-reconfigure grub-efi-amd64-signed /usr/sbin/dpkg-reconfigure: grub-efi-amd64-signed is broken or not fully installed. ➜ ~ sudo apt install grub-efi-amd64-signed Reading package lists... Done Building dependency tree Reading state information... Done grub-efi-amd64-signed is already the newest version (1.93.3+2.02-2ubuntu8.2). 0 to upgrade, 0 to newly install, 0 to remove and 1 not to upgrade. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Setting up grub-efi-amd64-signed (1.93.3+2.02-2ubuntu8.2) ... Installing for x86_64-efi platform. Could not delete variable: Invalid argument grub-install: error: efibootmgr failed to register the boot entry: Block device required. dpkg: error processing package grub-efi-amd64-signed (--configure): installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1 Errors were encountered while processing: grub-efi-amd64-signed E: Sub-process /usr/bin/dpkg returned an error code (1) ➜ efi ls -l total 5284 drwxr-xr-x 5 root root 4096 Apr 4 2015 Boot -rwxr-xr-x 1 root root 1615712 Apr 4 2015 bootmgfw.efi -rwxr-xr-x 1 root root 427680 Apr 4 2015 bootmgr -rwxr-xr-x 1 root root 1612128 Apr 4 2015 bootmgr.efi drwxr-xr-x 3 root root 4096 Jul 16 10:52 boot-repair -r-xr-xr-x 1 root root 512 Jul 29 2015 BOOTSECT.BAK drwxr-xr-x 3 root root 4096 Apr 4 2015 DELL drwxr-xr-x 7 root root 4096 May 30 2015 EFI drwxr-xr-x 2 root root 4096 Apr 4 2015 en-us -rwxr-xr-x 1 root root 1183744 Jan 1 1980 FSCK0000.REC -rwxr-xr-x 1 root root 106496 Jan 1 1980 FSCK0001.REC -rwxr-xr-x 1 root root 427680 Apr 4 2015 NTLDR drwxr-xr-x 2 root root 4096 Apr 4 2015 sources -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1753518 Title: package grub-efi-amd64-signed 1.93+2.02-2ubuntu8 failed to install/upgrade: installed grub-efi-amd64-signed package post- installation script subprocess returned error exit status 1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2-signed/+bug/1753518/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
