I am currently trying to do a completely unattended Ubuntu install with preseed, following AskUbuntu automated install instructions.

Everything works fine on VirtualBox (I am simulating a DVD) but when I try to burn my ISO on a USB stick and boot it on a computer (UP Squared with Intel CPU), it doesn't boot !

I'd like to add : I have no problem with my bootable key when using a standard ubuntu installation. On the discussion I linked above, best answers says to "burn it on a DVD". Is there a difference between a burn DVD and a bootable USB key ?

Thanks in advance.

  • 1
    Did you treat your iso file with isohybrid to make it a hybrid iso file? In that case it should work to clone it to a working USB boot drive. See this link.
    – sudodus
    Commented Jun 5, 2018 at 18:38
  • 2
    Maybe the method of the following link can help, How can I make a bootable, unattended USB restore disk?
    – sudodus
    Commented Jun 5, 2018 at 19:15
  • @sudodus isohybrid seem to do the trick ! Many thanks :)
    – erenaud
    Commented Jun 6, 2018 at 12:49

2 Answers 2


As @sudodus pointed out, I needed to treat my iso with isohybrid.


Can I ask how you burned your ISO? If you used Unetbootin by any chance, it might be possible that the liveUSB has no boot flag.This bug has been around for a while. And if the liveUSB isn't recognised as bootable... it doesn't boot.

You can solve this with GParted. Select the USB drive, and do a right click. A menu will open which holds "Manage flags". If you click that another menu opens, where you can select "boot". After you've done this, close GParted and (re)boot from the liveUSB.

  • Hi ! Thanks for your answer. I simply used Startup Disk Creator (USB-creator).
    – erenaud
    Commented Jun 6, 2018 at 8:05

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