Well thanks, that was the planscdbackup wrote: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.


It just reads the file bootpart.bin and creates a partition of it. You can put anything you want into it. (But creating a FAT image out of a directory wouldn't increase its complexity much. I was thinking about adding that too, but then I just used mkfs.vfat from the Makefile because I'm lazyscdbackup wrote:Although the opportunities to add payload seem extremely sparse.)

Yes, all of them (at least all that I can test with). MBR type 0xef is there only for legacy systems and legacy tools to avoid accidental overwrite of the GPT. I can't boot the image under UEFI without an ESP in a GPT. (When I boot in legacy CSM, the /EFI/BOOT/BOOTX64.EFI file is not used at all, then it takes the x86_64-bios route.)scdbackup wrote: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 ?
You can only boot from the MBR with CSM, and does not work on modern machines which has no legacy CSM boot option. It is said that UEFI manufacturers will remove CSM this year, but I can imagine they'll still support it a bit longer, few more years perphaps, no more.scdbackup wrote:(I ask because the GPT in ISOLINUX isohybrid for EFI is invalid and EFI
is supposed to boot via MBR partition table.
Not a good idea. There are lots of advantages in GPT over MBR. First, you can have more than 4 partition records. Second, you have larger sector number fields which can describe the capacity of disks these days.scdbackup wrote:So i preach for abandoning the GPT entirely.
Yes, I was talking about standard VBRs, not hybrid ones. Hybrid boot sectors tend to have everything, because they are hybridscdbackup wrote:> 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

Oh, right! Should had more sleep I guess. 32k it is! Anyway the point is you have enough space to put a GPT there.scdbackup wrote:> 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.
Cheers,
bzt