From mucking around in the grub rescue mode it seems as it doesn't have
msdos filesystem support.
On 29/04/2014 5:06 PM, "Daniel Walton" <bts@bts.grml.org> wrote:

>
> New submission from Daniel Walton <daniel.walton@gmail.com>:
>
> Have tried two methods to boot USB disks using EFI/UEFI
> ### 1. USB disk created using dd cdrom.iso > usb disk
> What steps will reproduce the problem?
>
> create usb disk by using dd/ddrescue onto a usb flash drive.
> in my case i used the following command after booting from the grml CD
>
> ddrescue --force /dev/cdrom /dev/sdb
>
>
> What is the expected output? What do you see instead?
> For PC and MAC (imac)
>   no UEFI boot option appears for the usb disk (grml 2013.9 installed to
> USB
> disk works fine)
>
>
> What version of the product are you using? On what operating system?
>
> Using grml 2014.03 full 96
> On a newish PC that allows UEFI as well as legacy booting methods.
>
> ### 2. USB disk created using "grml2usb /dev/cdrom /dev/sdb1" to usb stick
> with
> formatted fat32 partition
> What steps will reproduce the problem?
>
> make USB stick and then try to boot from a MAC or a PC with UEFI capability
>
>
> What is the expected output? What do you see instead?
>
> On PC& MAC the drive appears and shows it has EFI/UEFI booting capability
> but
> when you boot the following error occurs. (within the """ delimiters)
>
> """
> unknown command 'normal'.
> E: Could not find root device!
> Error: no such device: /conf/bootid.txt
> Entering rescue mode...
> grub rescue>
> """
>
> What version of the product are you using? On what operating system?
>
> Using grml 2014.03 full 96
>
> On a newish PC that allows UEFI as well as legacy booting methods.
>
> ----------
> messages: 4796
> nosy: daniel.walton
> priority: bug
> status: unread
> title: Unable to boot to USB disk using EFI/UEFI
>
> _____________________________________
> GRML issue tracker <bts@bts.grml.org>
> <http://bts.grml.org/grml/issue1306>
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>