Comment 15 for bug 1851955

Sorry for the late reply Steve. Here are the commands you asked for (which are consistent with what Ian reported and you observed):

$ sudo efibootmgr -o 0000,0003,0004,0001; echo $?
Invalid BootOrder order entry value0000,0003,0004
                                               ^
efibootmgr: entry 0004 does not exist
8
$ sudo efibootmgr -o 0000,0003,0001; echo $?
Could not set BootOrder: Invalid argument
8
$

Running "sudo dpkg --configure -a" yeilded:

$ sudo dpkg --configure -a
Setting up grub-efi-amd64-signed (1.128.1+2.04-1ubuntu12.1) ...
Installing for x86_64-efi platform.
grub-install: warning: Cannot set EFI variable Boot0000.
grub-install: warning: efivarfs_set_variable: writing to fd 7 failed: Invalid argument.
grub-install: warning: _efi_set_variable_mode: ops->set_variable() failed: Invalid argument.
grub-install: error: failed to register the EFI boot entry: Invalid argument.
dpkg: error processing package grub-efi-amd64-signed (--configure):
 installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
dpkg: dependency problems prevent processing triggers for shim-signed:
 shim-signed depends on grub-efi-amd64-signed | grub-efi-arm64-signed; however:
  Package grub-efi-amd64-signed is not configured yet.
  Package grub-efi-arm64-signed is not installed.

dpkg: error processing package shim-signed (--configure):
 dependency problems - leaving triggers unprocessed
Errors were encountered while processing:
 grub-efi-amd64-signed
 shim-signed
$