[syslinux] Using syslinux on the PMBR of a GPT partition table

[Stewart Adam]

On 10/29/08 6:21 PM, Stewart Adam wrote:
> On 10/29/08 12:48 PM, H. Peter Anvin wrote:
>> Right, OK.  For gptmbr.bin to work, it needs the UUID of the boot
>> partition written into offset 424.  However, there seems to be more that
>> goes wrong in your case.
>>
>> Perhaps you could even get me an image to download that I could poke
>> around with.
>>
>> 	-hpa
>>
> I have a slow upload cap so I won't be able to give you the full 700MB
> image, but it's easy to reproduce the content of the USB key:
>
> 1. Check out Fedora's livecd-tools from Git [1]
> 2. Apply to this [2] patch to tools/livecd-iso-to-disk.sh
> 3. Download the Fedora 10 Snapshot 3 ISO
> 4. Run tools/livecd-iso-to-disk.sh --mactel --format path/to/iso /dev/sdx
>
> [1] http://git.fedoraproject.org/git/?p=hosted/livecd
> [2] http://downloads.diffingo.com/livecd-iso-to-disk.sh-efi.patch
>
> P.S. If there's an easier way to do this (ie if you only need the first
> 10ish MB of the key), let me know and I'll send you the sample.
>
> Thanks,
> Stewart

Just to give you some more debugging info, I tried creating a gptmbr.bin 
file with the GPT GUID appended. The total file size was 460 bytes, which 
according to Wikipedia sounds right ;)

I copied it to /dev/sdb, but some things I found weird is that this time, 
instead of showing a blank screen booting from the BIOS does fail with a 
"Cannot find boot partition" message. As well, parted shows this message 
when opening /dev/sdb:
Warning: /dev/sdb contains GPT signatures, indicating that it has a GPT 
table. However, it does not have a valid fake msdos partition table, as it 
should. <...>

I rebooted into OS X to check, and indeed it looks like something is wrong 
with the GPT partition table:

# sudo diskUtil list /dev/disk1
/dev/disk1
    #:                       TYPE NAME                    SIZE       IDENTIFIER
    0:                                                   *3.7 Gi     disk1

I'm going to try to create a GPT layout within OS X and then copy the Live 
OS onto that partition to see if that helps.

BTW - Is there an easy way to get the GUID of a partition from Linux?

Stewart