I had installed Debian on my external HDD but for some reasons GRUB didn't get installed on the HDD EFI partition but instead on has been installed on the man disk where I was doing the Debian install.
I would like instead to 're' install manually GRUB with the grub-install binaries in the EFI partition of my HDD like that I can simply plug it in any computer I be able to boot into Debian.
I'm unsure how to do it with grub-install.
lsblk gives (removes the other disks):
sdd 8:48 0 931.5G 0 disk
├─sdd1 8:49 0 200M 0 part /mnt/efi
├─sdd2 8:50 0 819.4G 0 part /media/ubuntu/John
├─sdd3 8:51 0 104G 0 part /media/ubuntu/992fa2fd-51db-493b-92bb-bc08379fd996
└─sdd4 8:52 0 7.9G 0 part
what argument should I pass to grub install?
grub-install sdd1 ?
or
grub-install --efi-directory=/mnt/efi?
(I have mounted myself sdd1 to /mnt/efi) (I'm doing this from a live Unbuntu usb)