当我从 21.10 升级到 22.04 LTS 时，我遇到了最后一个错误：
root@reaper /opt # apt upgrade
Reading package lists... Done
Building dependency tree... Done
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] y
Setting up grub-efi-amd64-signed (1.180+2.06-2ubuntu7) ...
mount: /var/lib/grub/esp: special device /dev/sda15 does not exist.
dpkg: error processing package …upgrade ×1