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quarksrus avatar Ubuntu

Ubuntu 21.04 Cannot Boot From External USB HDD

ke flag
quarksrus

My filesystem layout, internal is sda and external is sdb:

sda                                                                             
├─sda1                                                                          
├─sda2                                                                          
├─sda3 xfs                  47a37509-ff0a-428d-915c-bb4f0990db3f    1.8G     8% /boot
├─sda4 xfs                  ccbf4efa-8634-43f8-806a-118b9295471c   41.1G    18% /
├─sda5 swap     1           ace29398-f6ce-41a6-83ea-fafeb00ae323                [SWAP]
└─sda6 xfs                  563b68c5-8f7d-48c7-a0c8-1b3e7e7fc276  843.9G     4% /home
sdb                                                                             
├─sdb1                                                                          
├─sdb2                                                                          
├─sdb3 ext4     1.0         abad4358-f108-4521-b8f8-4b7ff0f67c2e                
├─sdb4 ext4     1.0         a9cd1ec5-bcab-4a03-9ae3-86a776821e08                
├─sdb5                                                                          
└─sdb6 ext4     1.0         1368841e-d836-4e79-81e1-9a0a6db1aa61

Steps done so far:

  1. Used the clone-ubuntu.sh script to clone the internal hdd to a 2TB external hdd.
  2. Ran 'grub-install /dev/sdb' and ran 'update-grub' when booted off the internal drive.
  3. Mounted /dev/sdb3 to /mnt.
  4. Updated the /mnt/grub/grub.cfg file with the UUID of the /dev/sdb for /boot partition.
  5. Updated the /mnt/grub/grub.cfg file with the UUID of the /dev/sdb for / partition.
  6. Updated the /mnt/grub/grub.cfg file and changed from hd0,gpt4 to hd1,gpt4

It's an old Acer Aspire One laptop with BIOS (no UEFI) and I change the boot order with the external drive as the first boot device. And everytime it boots off the internal drive, I can't make it to boot off the external drive.

What am I doing wrong? Did I miss a crucial step or something? I even ran 'dd bs=512 count=1 if=/dev/sdb 2>/dev/null| strings ZRr= `|f |f1 GRUB Geom Hard Disk Read Error

and as you can see it does contain GRUB!

I'm at a total loss, any help is greatly appreciated.

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guiverc avatar
cn flag
guiverc
Some devices (*controlled by the device firmware*) have specific rules that must be met. I have *dell* devices that will only boot an external disk if it's the only USB connected storage device (ie. no thumb-drives, or single disk only installed; some USB devices have storage in them, so that includes some hubs in my experience cannot be used), I also have devices that will only boot *external* devices if a key is used to select boot device during boot (even if the BIOS is set to allow external boot above internal). These issues are regardless of OS in my experience as *firmware* specific.
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C.S.Cameron avatar
cn flag
C.S.Cameron
I have best luck unplugging internal drives before installing to external drives. New install should be in same BIOS/UEFI mode as existing.
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quarksrus avatar
ke flag
quarksrus
Thanks but I figured out the issue. Looks like the clone-ubuntu script only works with ext4 fs types and not xfs. The partitions on the original drive are all xfs but clone-ubuntu requires that they be ext2/4 on the clone drive. I did this but forgot to update the fs type in /etc/fstab on the clone drive. Once I updated it, I was able to boot from the clone drive!!
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