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I am trying to install ubuntu from a usb stick on a uefi environment. I have previously succeded following the iso-loopback method explained at How to create UEFI-only bootable USB live media?

Now I have the following problem. If I use the Ubuntu Desktop 16.04 amd64 iso, I can boot ubuntu from the live usb stick. But in all the different laptops that I have tried using the 16.04.1 iso, I end up with a grub command line. When I try to invoke the loopback command I get

grub> loopback loop [path_to_iso]
error: can't find command 'loopback'

and insmod loopback doesn't find the loopback.mod file.

I have disabled secure boot. The md5sums for the iso images are correct. Using the 16.04 iso image works well, but the 16.04.1 doesn't. I am copying the files to a freshly formatted usb stick.

I want to boot from the 16.04.1 image to reduce the amount of downloads when updating. Would you please suggest how to fix this issue?

Thank you.

Community
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Homero Gallegos
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  • looback? or is that typo just in your post? – oldfred Feb 16 '17 at 22:07
  • Did you set variable root to the disk and partition containing the grub files? – ubfan1 Feb 16 '17 at 22:52
  • @oldfred It is a typo. I couldn't copy and paste, since it was the startup screen. – Homero Gallegos Feb 16 '17 at 23:25
  • @ubfan1 I am trying to set up a dual boot along Windows 10. On the partitions on the hard drive of the computer there is no grub at all. I am trying to boot from a usb-stick. Since I am using the loopback method, I have no access to the file tree and I can't set the root variable to the grub folder on the iso image. – Homero Gallegos Feb 16 '17 at 23:28
  • I have used loopback method to directly boot ISO from BIOS & UEFI flash drives and HDD. But issue almost always is getting path correct. And with UEFI, I typical have a full install of Ubuntu on larger flash drive. But have directly installed grub for UEFI and manually created my own grub.cfg This was my old BIOS version: http://askubuntu.com/questions/388382/multi-partition-multi-os-bootable-usb/388484#388484 & Have not tried this: https://ubuntuforums.org/showthread.php?t=2276498 & http://askubuntu.com/questions/549647/uefi-machine-doesnt-boot-ubuntu-through-nvram-bootcatalog-how-to-fix – oldfred Feb 16 '17 at 23:43
  • The root should be to the USB, something like set root='hd0,msdos1' That should let grub find its modules, then then loopback command should work. – ubfan1 Feb 17 '17 at 00:12
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    Thank you for your replies. I gave up using the loopback method. I tried setting up root to (hd0), which was the usb stick, but it kept complaining that it didn't find its modules. I had compiled the grubx64.efi by hand and it works with older iso's. It doesn't with 16.04.1. I have now used ubuntu startup disk creator and though I ended up again at the grub prompt, I was now able to set root to the appropriate folder on the file tree. Ubuntu 16.04.1 is now being installed. – Homero Gallegos Feb 17 '17 at 00:18
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    Nevertheless, I am very curious about why grub finds its modules on older iso's, and doesn't find them with this specific 16.04.1 image. – Homero Gallegos Feb 17 '17 at 00:24

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