grub-efi-amd64-signed package post-installation script subprocess returned error exit

[Valtam]

Having given this a great deal of thought, the following is the best remedy.

After you have run Install Updates, open a Terminal, do:

Code:

wget -O grub-efi-fix-74.sh https://www.linuxliteos.com/files/grub-efi-fix-74.sh && chmod +x grub-efi-fix-74.sh && sudo ./grub-efi-fix-74.sh

enter your password and let the script finish. (fully automated process)

Reboot and run Install Updates again, to verify there are no more errors.

What does it do?

# Try detecting EFI partition from /boot/efi
# Fallback method using lsblk if findmnt fails
# Final check
# Ensure debconf-utils is installed
# Preseed GRUB install device
# Run dpkg configuration non-interactively
# Optional: Reinstall GRUB to EFI (only if needed)
# Update grub config