Ubuntu external SSD only boots on computer used to install

sudoer

7/12/24, 6:37 AM

I installed Ubuntu 23.04 Desktop with new installer from live USB onto my external SSD. There are only 3 partitions:

/boot/efi (FAT)
/ (Ext4)
(another data partition as exFAT used as regular storage)

For the installation, I disabled boot and esp flags on my internal Windows SSD. Next, I choose "manual partition" and selected the bootloader to be installed on the external SSD. For all I have done, all computers aside the one I installed Ubuntu with boot into Windows even if choose the external SSD in the BIOS boot menu.

I searched for "truly portable ubuntu installation" on Google, which directed me to this link. I tried to follow the instructions but failed. Either I misunderstood or it is not applicable in my case ("If you see a ‘dual boot’ Grub option screen - then everything that follows applies") - I don't see the ‘dual boot’ Grub option screen.

First things first, how can I confirm the location of Grub? If it is really on the internal SSD (which I doubt so), how can I move Grub to external SSD? Otherwise, why can't I boot Ubuntu other computers?

Any help would be appreciated. I usually reply in a matter of minutes.

0 + 6

boot

grub2

external-hdd

guiverc

7/12/24, 6:41 AM

You mention a release (23.04) but not what product or ISO for that release (if it's 23.04 Desktop - two ISOs that use different installers are available; if *flavor* then different installers can also be involved let alone Server using a different installer) so its helpful if you're specific. The link you gave mentions C.S.Cameron on this site - I'd go for *C.S.Cameron's* advice firstly personally (*not that I know your quoted article; but details look rather old & aren't that specific or clear with details as I'd have questions before using it!*)

sudoer

7/12/24, 6:44 AM

Clarified in edited question.

sudoer

7/12/24, 10:02 AM

I thought of using `grub-install` command. Is that the way to go?

oldfred

7/12/24, 1:56 PM

Check UUID mount of ESP - efi system partition in /etc/fstab. If UUID of external drive, you just need to boot in UEFI mode & reinstall grub. `cat /etc/fstab` & `lsblk -e 7 -o name,fstype,size,fsused,label,partlabel,mountpoint,parttype` If same: `sudo grub-install`. Uses many default options, otherwise normally required.

sudoer

7/12/24, 3:24 PM

I can't find the two commands same. But using `lsblk -f` and `cat /etc/fstab` shows same UUID for /dev/sda1 which is mounted at /boot/efi. So can I run `grub-install` in this case? Or is further inspection required?

sudoer

7/13/24, 11:58 PM

@oldfred I tried running that command anyways. I doubt if it took any effect and did it work.

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