Unable to install grub in /dev/sda

[Ralf Mardorf]

On Sat, 16 Oct 2021 23:31:35 +0000, Phil Fraser wrote:
>I'm desperate to find a solution because I'm without my beloved Linux
>except for the live USB key.

Hi,

try to install it from your live USB by a chroot

https://help.ubuntu.com/community/Grub2/Installing
https://help.ubuntu.com/community/UEFI

https://howtoubuntu.org/how-to-repair-restore-reinstall-grub-2-with-a-ubuntu-live-cd

Depending on what is missing, grub can be installed even without a
chroot. When I used grub, I've reinstalled it without a chroot, but in
your situation a chroot might be the better approach. I never used UEFI
mode, let alone that I migrated to syslinux a long time ago.

Btw. a few days ago I mentioned that systemd-nspawn can't always
replace a chroot. In my experiences using systemd-nspawn to reinstall
grub doesn't work.

Disclaimer: Today I didn't read the links I provided. However, I've
taken a look at the history of the first help.ubuntu.com link. It was
edited 25 times from 2012 to 2015 and before users are allowed to edit
it, they need to join the ubuntu-wiki-editors team. While
howtoubuntu.org is new to me, contributions are obviously done by a
GitHub repository. IOW those howtos are "under control", it should be
safe to follow those advices.

Regards,
Ralf