grml liveUSB does not appear as UEFI

Question

I'm trying to repair my broken linux install with grml, since I hear it has EFI support, which I need for what I'm trying to do. Specifically, I need to see a 'UEFI:' prefix before my liveUSB drive when choosing it from the boot menu. So, I downloaded the latest grml ISO, and dd'd it to my usb (dd if=grml64-full_2013.02.iso of=/dev/sde), but I'm not seeing the necessary 'UEFI:' prefix from the boot menu.

If my understanding of UEFI/EFI is correct, this happens when the bootloader finds a 'bootx64.efi' file, which is present in my drive (efi/boot/bootx64.efi), but maybe in the wrong location?

Is it possible to get a proper liveUSB with grml2usb? From reading its manpage, I don't see any UEFI/EFI options?

Edit: actually, this is what my GRML liveUSB looks like, according to mount:

/dev/sde1 on /media/grml64-full 2013.02 type iso9660 (ro,nosuid,nodev,relatime,uid=1000,gid=1000,iocharset=utf8,mode=0400,dmode=0500,uhelper=udisks)
/dev/sde2 on /media/GRML type vfat (rw,nosuid,nodev,relatime,uid=1000,gid=1000,fmask=0022,dmask=0077,codepage=cp437,iocharset=utf8,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks)

And indeed, /dev/sde2 appears to contain nothing but /EFI/BOOT/bootx64.efi

And if it's relevant, my motherboard is an Asus P8P67, which only has UEFI available, my processor is x86_64.

Answer 1

Turns out I just needed to follow the "Building an EFI USB Key on a Mac" instructions. The steps for gparted are extremely similar.

1. With the appropriate /dev/sdX selected, select menu option Devices > Create partition table
2. In the dialog that follows, expand the 'Advanced' option and change 'msdos' to 'gpt' and click apply.
3. Right click the unformatted partition, select 'New'
4. Make it FAT16 or FAT32
5. Unpack the iso and copy its files directly into the empty FAT partition