Jonathan Omisore

When I attempted to install Arco Linux on my external hard drive, I faced a glitch in which the Calameres installer decided to install GRUB on my computer’s internal hard drive rather than my external hard drive. Here is how I solved this problem.

First boot into a live Linux USB with the external hard drive connected to your computer.

List all partitions to identify the EFI partition and the Linux partition

lsblk

Suppose /dev/sdb1 is the Linux partition and /dev/sdb2 is the EFI partition. Mount the Linux partition to /mnt and the EFI partition to /mnt/boot/efi

sudo mount /dev/sdb1 /mnt
sudo mount /dev/sdb2 /mnt/boot/efi

Mount special locations

sudo mount --rbind /proc /mnt/proc
sudo mount --rbind /dev /mnt/dev
sudo mount --rbind /sys /mnt/sys

Chroot into the mounted path

sudo chroot /mnt

Install GRUB to the external hard drive

sudo grub-install /dev/sdb

Update GRUB

sudo update-grub

But you aren’t finished yet. You need to make sure your computer knows to boot into your EFI partition. Find the UUID of your EFI partition

blkid

Edit fstab

cp /etc/fstab /etc/fstab.bak  
sudo nano /etc/fstab  

Add the following line, setting the value of UUID equal to the UUID you obtained from the blkid command.

UUID=   /boot/efi   vfat   umask=0077   0   1  

Now reboot into your external hard drive.