Setting up grub-efi-amd64-signed (1.66.14+2.02~beta2-36ubuntu3.14) ...
Installing for x86_64-efi platform.
grub-install: error: /boot/efi doesn't look like an EFI partition.
.
dpkg: error processing package grub-efi-amd64-signed (--configure):
Is there a reason /boot/efi is not mounted on your system? It is always set up as part of the installation of Ubuntu. Please attach /etc/fstab from this system.
Your log shows:
Setting up grub-efi- amd64-signed (1.66.14+ 2.02~beta2- 36ubuntu3. 14) ... amd64-signed (--configure):
Installing for x86_64-efi platform.
grub-install: error: /boot/efi doesn't look like an EFI partition.
.
dpkg: error processing package grub-efi-
Is there a reason /boot/efi is not mounted on your system? It is always set up as part of the installation of Ubuntu. Please attach /etc/fstab from this system.