How to solve a UEFI error when installing Escuelas Linux 8.x

We have noticed that on certain UEFI machines, the installation of Escuelas Linux 8.x fails with an error message when trying to install the boot loader:

grub-install -target =x86_64-efi -efi-directory=/boot/efi -bootloader-id=ubuntu -force returned error code 1

If this problem occurs on your computer and it is connected to the Internet, open Terminology and type

1. sudo apt-get update [enter]
2. Type your password [enter]

Note: If you get a message about inserting a disk into /media/cdrom, press CTRL-C and type

sudo leafpad /etc/apt/sources.list [enter]

Place the # symbol before the words deb cdrom on the third line, press File → Save, close the Leafpad window and return to step 1.

3. sudo apt-get install boot-repair [enter]
4. sudo boot-repair [enter]

Alternatively, if the computers with this problem do not have an Internet connection, you may need to download beforehand the Boot Repair disk, available at

https://sourceforge.net/projects/boot-repair-cd/

At the "Files" menu, download the ISO image and process it on a USB stick with at least 4 GB of free space.

To process the ISO image, you can use Balena Etcher, which comes preinstalled with Escuelas Linux in Menu → Applications → Utilities → balenaEtcher. You can also download it from its official portal for other OSes and distributions.

After boot-repair-disk does its magic, it also adds a lot of entries to the GRUB menu, where you can choose which OS to boot. You may want to have only the entries for "Escuelas Linux", "Advanced Options for Escuelas Linux" and "Windows Boot Manager". To do so, you can comment out all the additional entries created by Boot Repair by editing grub.cfg. Open Terminology and type:

sudo leafpad /boot/grub/grub.cfg [enter]
Type the password [enter]

Add a "#" at the start of each line of the menuentry that you do not want to appear in the grub menu. Remember to also add a # to the closing "}" symbol of each commented menuentry.