Discussion:
[Grml] partition tables
Lupe Christoph
2013-04-21 10:13:29 UTC
Permalink
Hi!

I just wrote GRML 96 Full 2013.02 to a new USB stick and wanted to
adjust the partition table. But that wasn't valid (I'll demonstrate
using the ISO):

------------------------------------------------------------------------
$ fdisk -l /sw/archive/grml/grml96-full_2013.02.iso

WARNING: GPT (GUID Partition Table) detected on '/sw/archive/grml/grml96-full_2013.02.iso'! The util fdisk doesn't support GPT. Use GNU Parted.

$ gdisk -l /sw/archive/grml/grml96-full_2013.02.iso
GPT fdisk (gdisk) version 0.8.5

Partition table scan:
MBR: MBR only
BSD: not present
APM: not present
GPT: present

Found valid MBR and GPT. Which do you want to use?
1 - MBR
2 - GPT
3 - Create blank GPT

Your answer: 1
Warning! Main partition table overlaps the first partition by 34 blocks!
You will need to delete this partition or resize it in another utility.

Warning! Secondary partition table overlaps the last partition by
33 blocks!
You will need to delete this partition or resize it in another utility.
Disk /sw/archive/grml/grml96-full_2013.02.iso: 1497088 sectors, 731.0 MiB
Logical sector size: 512 bytes
Disk identifier (GUID): EE7463AF-ED0A-4537-A878-963CCF70DFD9
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1497054
Partitions will be aligned on 2048-sector boundaries
Total free space is 0 sectors (0 bytes)

Number Start (sector) End (sector) Size Code Name

$ gdisk -l /sw/archive/grml/grml96-full_2013.02.iso
GPT fdisk (gdisk) version 0.8.5

Partition table scan:
MBR: MBR only
BSD: not present
APM: not present
GPT: present

Found valid MBR and GPT. Which do you want to use?
1 - MBR
2 - GPT
3 - Create blank GPT

Your answer: 2
Using GPT and creating fresh protective MBR.
Warning! Main partition table overlaps the first partition by 34 blocks!
You will need to delete this partition or resize it in another utility.
Disk /sw/archive/grml/grml96-full_2013.02.iso: 1497088 sectors, 731.0 MiB
Logical sector size: 512 bytes
Disk identifier (GUID): 7A9EDD46-5620-4D0E-B375-F3D2B5CB6FC1
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1497054
Partitions will be aligned on 64-sector boundaries
Total free space is 642 sectors (321.0 KiB)

Number Start (sector) End (sector) Size Code Name
2 1459520 1461247 864.0 KiB 0700 ????d?????
------------------------------------------------------------------------

We'll I can't read Chinese, maybe somebody can translate? ;-)

The stick boots OK in MBR mode on a SONY VAIO with UEFI.

I found strange partition tables on other ISOs, even older ones.

Can you investigate how these partition tables are generated and fix
that? It would be useful if you could change them on the stick with
fdisk.

Thank you!
Lupe Christoph

PS: I'll use grml2usb for now.
--
| It is a well-known fact in any organisation that, if you want a job |
| done, you should give it to someone who is already very busy. |
| Terry Pratchett, "Unseen Academicals" |
Michael Prokop
2013-04-22 10:08:57 UTC
Permalink
Hi,
Post by Lupe Christoph
I just wrote GRML 96 Full 2013.02 to a new USB stick and wanted to
adjust the partition table. But that wasn't valid (I'll demonstrate
------------------------------------------------------------------------
[...]
Post by Lupe Christoph
$ gdisk -l /sw/archive/grml/grml96-full_2013.02.iso
GPT fdisk (gdisk) version 0.8.5
[...]
Post by Lupe Christoph
Disk /sw/archive/grml/grml96-full_2013.02.iso: 1497088 sectors, 731.0 MiB
Logical sector size: 512 bytes
Disk identifier (GUID): 7A9EDD46-5620-4D0E-B375-F3D2B5CB6FC1
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1497054
Partitions will be aligned on 64-sector boundaries
Total free space is 642 sectors (321.0 KiB)
Number Start (sector) End (sector) Size Code Name
2 1459520 1461247 864.0 KiB 0700 ????d?????
------------------------------------------------------------------------
We'll I can't read Chinese, maybe somebody can translate? ;-)
Google Translate says:

"Hui ? approved Wei d Zhen, ? Rong> hammer"

;)
Post by Lupe Christoph
The stick boots OK in MBR mode on a SONY VAIO with UEFI.
I found strange partition tables on other ISOs, even older ones.
Can you investigate how these partition tables are generated and fix
that? It would be useful if you could change them on the stick with
fdisk.
Well, this is caused by isohybrid which we're running with the
"--uefi" option to get those hybrid ISOs.

So if you'd like to see this changed you'd have to bug isohybrid's
upstream (being the syslinux maintainers). But I'm not too
optimistic there exists a reliable way to change that since hybrid
ISOs (and therefore the isohybrid tool) are using quite some hacks
to work on all/most machines and that's what you're currently
seeing in the MBR of the ISOs. ;)
Post by Lupe Christoph
PS: I'll use grml2usb for now.
Yeah, that's actually the recommended way to get flexible systems. :)

regards,
-mika-
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