Problème initial, à la fin de l'installation de Linux Mint 19.1 :
«grub-efi-amd64-signed failed to install into /target/. Without GRUB boot loader,
the installed system will not boot»

Pas encore tester les solutions :
https://askubuntu.com/questions/789998/16-04-new-installation-gives-grub-efi-amd64-signed-failed-installation-target
https://askubuntu.com/questions/400400/ubuntu-12-04-grub-efi-amd64-signed-failed-to-install-into-target
https://help.ubuntu.com/community/Boot-Repair
https://www.learningpenguin.net/2018/07/13/fix-grub-efi-amd64-signed-package-failed-to-install-into-target/
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