On Dec 12, 2013, at 8:03 AM, Pasha R <pashar.ml@gmail.com> wrote:

An issue I recently encountered: USB created with dd or LiveUSB creator might not boot on EFI systems.

That bug with Live USB Creator should be fixed.
https://bugzilla.redhat.com/show_bug.cgi?id=810112

There might be a bug related to the ISO image, which contains a really unit partition map structure to enable it to boot both BIOS and UEFI systems, whether the media is 512 byte (USB sticks) or 2048 byte (DVDs) physical sectors. To any partition tool it will appear to be corrupt. It's not, it's just unique to fit this purpose. But this has been quite heavily tested over the past 18-24 months so I more likely suspect a firmware bug. But there can also be other boot related issues now that Secure Boot is supported so it's important to file bugs and be really clear about what *does* happen rather than saying it "doesn't boot" which isn't descriptive enough.


The only tool that worked for me was livecd-iso-to-disk with --efi option (required me to add --format, too, so it is destructive).

I vaguely recall some unexpected behavior with --format or maybe the combination of --format with --reset-mbr. But there is some weirdness with LITD in that the --efi option *adds* EFI boot support to a tool that creates BIOS bootable media. So you actually are not getting exclusively EFI boot media, but rather hybrid boot media. Therefore the --reset-mbr is required if the first 440 bytes of LBA0 do not contain BIOS boot code. This is confusing for those who know that such code is ignored on EFI systems. 

Anyway, my expectation is if I specify /dev/sdb2 for installation, and use --format --efi --reset-mbr that all other partitions are preserved, but I'm pretty sure that combination blows away the whole partition map and all content on the stick. But it does warn of this also and enables a safe exit via control-C. To me, --format implies using mkfs.vfat -F32 on the specified partition, but that doesn't appear to be the only thing it does.


Chris Murphy