Hi,
for ISOLINUX isohybrid from a partition instead of a base device see
https://wiki.syslinux.org/wiki/index.ph ... _selection
I am not aware whether GRUB would offer MBRs for that purpose. Its
official control program for making bootable ISOs offers no option for
preparing an ISO image for putting into a partition.
obivac wrote:
> what exactly do tools like Xorriso do that's different from just using dd
On the one hand xorriso packs up input files as payload of an ISO 9660
filesystem. On the other hand it advertises the block addresses and sizes
of boot image files in the ISO, which the computer firmware can use to
start an operating system. This advertisement is in form of El Torito
boot information
https://wiki.osdev.org/El-Torito
or of a partition table
https://wiki.osdev.org/EFI_System_Partition
or simply x86 machine code at the start of the ISO 9660 image.
bzt wrote:
> And here's my hybrid PMBR GPT/ISO9660 image creator: mkimg.c
Wow. That's much smaller than any other ISO 9660 producer i know of.
Although the opportunities to add payload seem extremely sparse.

)
You take the effort to produce a GPT. Do you know of EFI implementations
which would not boot from an MBR partition of type 0xef ?
(I ask because the GPT in ISOLINUX isohybrid for EFI is invalid and EFI
is supposed to boot via MBR partition table. For most Linux distro ISOs it
seems to work. So i preach for abandoning the GPT entirely.)
------------------------------------------------------------------------
Anectotes and nitpicking:
> Volume Boot Record (VBR): [...] the first sector of a file system volume
> [...] There's no partitioning table in it for sure.
Well, someone should have told this program "mformat", which places a
partition table inside its FAT image if called like in
http://git.savannah.gnu.org/cgit/grub.g ... cue.c#n812
Some antique EFI really took offense and cycled endlessly.
> the first 64k is not used at all
It's the first 32k of an ISO 9660 filesystem, to be exacting.
At offset 32k comes the PVD, which is kindof the superblock of ISO 9660.
Have a nice day
Thomas