Okay, many thanks, Pascal. So I ran
grub-install --force-extra-removable and it reported no error. How likely is this to work with the new motherboard? I assume that I'll have to ask the engineer ot make sure the removable path is tried, too? Is there any package I should upgrade to at least some minimal version before maybe runing the command again, to make sure the firmware is recent enough? Thanks, Sébastien.
