user@m5:~$ sudo apt-get upgrade
sudo: unable to resolve host m5
[sudo] password for user:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  netplan.io ubuntu-advantage-tools
0 upgraded, 0 newly installed, 0 to remove and 2 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 linux-image-4.15.0-171-generic (4.15.0-171.180) ...
Processing triggers for linux-image-4.15.0-171-generic (4.15.0-171.180) ...
/etc/kernel/postinst.d/initramfs-tools:
update-initramfs: Generating /boot/initrd.img-4.15.0-171-generic
Warning: couldn't identify filesystem type for fsck hook, ignoring.
/etc/kernel/postinst.d/x-grub-legacy-ec2:
Searching for GRUB installation directory ... found: /boot/grub
Searching for default file ... found: /boot/grub/default
Testing for an existing GRUB menu.lst file ... found: /boot/grub/menu.lst
Searching for splash image ... none found, skipping ...
Found kernel: /boot/vmlinuz-4.15.0-33-generic
Found kernel: /boot/vmlinuz-4.4.0-134-generic
dpkg-query: error: package 'grub-legacy-ec2' is not installed
run-parts: /etc/kernel/postinst.d/x-grub-legacy-ec2 exited with return code 10
dpkg: error processing package linux-image-4.15.0-171-generic (--configure):
 installed linux-image-4.15.0-171-generic package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 linux-image-4.15.0-171-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)