➜  ~ sudo apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
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 (1.115+2.02+dfsg1-12ubuntu2) ...
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)