Am I constrained to run Ubuntu LIVE ISO's only on a bootable USB? All other distros aside - can I make a Bootable USB with an ISO something other than a LIVE ISO? To test this I expected I could make an ISO image myself using dd from my trustworthy robust installed Ubuntu 14.04 on /dev/sda1 SATA drive as the source. Then, I could use UNetBootin to write a Bootable USB for me using that ISO that I just made. So, I proceeded - and made sure my ISO was only 14Gbytes in size when I was done, as my USB stick is of the 16Gbyte variety. Used GPARTED to check the USB after UNetBootin was done with it, and added an extended swap partition in the leftover space on the USB. All looked well enough, but the USB stick doesn't boot up a PC. What's wrong with my reasoning? Am I constrained to run Ubuntu LIVE ISO's only on a bootable USB? :\ I'm Confused I guess... any thoughts?

1 Answer 1


Erm? You made an "ISO" with dd of an existing installation from a harddrive to use it with UNetbootin for setting up Ubuntu on an external drive?

That's one step too much and a very crude workaround: xkcd.com/763/

UNebootin is intended to be used with ISO images for optical media. If you dd something from your harddrive that's an image too, but not for optical media, and not what UNetbootin expects.

To install Ubuntu on external media like USB pendrives or external HDDs/SSDs, just choose this device during installation as a traget device (including the bootloader location) and the installer will set up everything for you.

Alternatively you can use dd to copy an existing installation to another device and install the bootloader on the device, but I would rather recommend copying of the files in the filesystem (use cp -a or rsync -a) instead of copying the entire filesystem and changing the UUIDs. This way you don't accidentally end up with the same UUID on multiple devices, which may get you into trouble. Also writing to certain types of storage with dd is harmful.

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To extend on why UNetbootin is not to be used with harddisk dump images: Live ISO images usually contain an image inside of the image which contains the Live environment and a special (non-standard) configuration to boot up this image from optical read only media. UNetbootin is a workaround to use these ISO images with USB storage devices. Actually you are using a workaround (UNetbootin) of a workaround (bootable system on optical read only media) and you where just trying to add another workaround on top (create an "ISO" to use it with UNetbootin).

  • You've indicated I can install Ubuntu to my USB device. That's great, I didn't know that. Booting Live ISO images on USB devices feels clunky and limited. Thank you for clearing up the issue that running Ubuntu fully installed on an electronic USB 3.0 stick (that isn't Read Only) is unlike running a live ISO from a CD or DVD or USB.
    – MisterE
    Commented Jan 8, 2015 at 21:59
  • @MisterE No problem. :) Don't forget to mark an answer as accepted, it will also give you some reputation points.
    – LiveWireBT
    Commented Jan 9, 2015 at 4:04

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