[syslinux] isohybrid --uefi - resulting EF00 partition too small
ms at mattiasschlenker.de
Tue Mar 12 07:23:19 PDT 2013
I am maintaining a distribution loosely based on LFS and am now trying
to add UEFI support. Integrating a FAT formatted partition image
containing, preloader, gummiboot, kernel and initramfs correctly results
in a ISO image that is bootable on BIOS and UEFI systems if booted from
the optical drive.
However, when I run
isohybrid --uefi name-of.iso
the resulting GPT entry for the EF00 partition is just 19MB. It should
be around 53MB:
root at barium:/tmp# gdisk -l
GPT fdisk (gdisk) version 0.8.5
Partition table scan:
MBR: MBR only
BSD: not present
APM: not 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 lesslinux-search-and-rescue-uluru-20130312-110347.iso: 1413120
sectors, 690.0 MiB
Logical sector size: 512 bytes
Disk identifier (GUID): 3F6E0DF3-466E-4B62-9BCC-14303CE24ADF
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1413086
Partitions will be aligned on 8-sector boundaries
Total free space is 514 sectors (257.0 KiB)
Number Start (sector) End (sector) Size Code Name
2 212648 251559 19.0 MiB 0700 卉䡏批楲d灁汰e灁汰
I have to note that all kernel modules and quite some binaries are part
of the initramfs, which is responsible for the large size. This has
never been a problem since the distribution is not intended for low
memory applications. Thus I assume the chinese characters say "Mattias,
you fucked it up!".
The ISO image was built using xorriso 1.1.8 (from Ubuntu 12.04) with the
xorriso -as mkisofs -graft-points -b boot/isolinux/isolinux.bin
-no-emul-boot -boot-info-table -boot-load-size 4 -c
boot/isolinux/boot.cat --efi-boot boot/efi.img -V
lesslinux-search-and-rescue-uluru-20130312-110347.iso -r cdmaster
--sort-weight 0 / --sort-weight 1 /boot
Isohybrid capability was added by using a statically linked isohybrid
binary built from the sources of syslinux 5.02pre3:
If you want to examine the resulting ISO image, it can be downloaded here:
Am I wrong with the assumption that it should be possible to create a
valid ISO image that boots on all four boot systems: BIOS-El-Torito,
UEFI-El-Torito, BIOS from MBR (respectively compatibility MBR) and UEFI
from EF00 partition mapped to the El-Torito image? Or did just my large
FAT image make me run into some side effects? If there will be no
possibility of supporting all four methods in one image I will move to
creating separate images for USB drives, something I outlined here
Of course in this case I would neither blame Thomas Schmitt nor Matthew
Garrett nor anyone else who did a great job on making isohybrid work for
so many use cases, neither would I blame my large initramfs - I think in
some cases it is just fate that jigsaw puzzle of four boot standards
does not fit together.
PS: Sorry for posting twice... Is the list initially moderated until
someone's first post is accepted? I sent this mail immediately after
subscribing and did neither receive a copy or find it in the archives.
Mattias Schlenker - Redaktion + EDV-Beratung + Linux-CD/DVD-Konzepte
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