On 06/11/19 21:41, Thomas Schmitt wrote:
Hi,
Nice to see you hanging around here ;-)
It's interesting to see what you are doing.
And after all, you are a user of xorriso. :))
? you are, I can't find it in the T2 package system anywhere? Or has it
been missed. It sounds like a good package to have available.
I noticed the other day that xorriso
Does not support -hfs as needed for bootable PowerPC Apple PowerMac
Yes. It has a HFS+ tree generator contributed by GRUB developer Vladimir
Serbinenko. He obviously had no interest in the older HFS-needy machines.
HFS and HFS+ are quite different, internally. I don't see an easy way to
derive -hfs from -hfsplus. And it's totally legacy.
You will have to use mkisofs or genisoimage.
Unrelated to this likely pure /efi/boot ISO
There is no EFI System Partition entry to see (for USB stick) and no EFI
El Torito item (for CD/DVD/BD). Both may well refer to the same block range,
a FAT filesystem. They just advertise this filesystem in different ways.
(Many EFI implementations don't care for the difference and boot CD via
partition table as well as USB stick via El Torito.)
But in t2-minimal-musl-clang-x86-64-r48750.iso there is no MBR signature,
no x86 code, and no MBR partition table in the first 512 bytes.
So there is no GPT (because of no "protective MBR") and thus no lure for
EFI firmware is present.
I see in the mounted ISO an EFI startup program for 64-bit x86:
/efi/boot/bootx64.efi
To be UEFI specs compliant, it would have to be in a FAT filesystem and
advertised by El Torito or partition table (MBR or GPT).
If you have boot success with this ISO, then probably because your EFI
looks in all regonizable filesystems for "\EFI\BOOT\BOOTX64.EFI". (The
UEFI specs show file paths in DOS style.)
For xorriso i advise to append the EFI System Partition FAT filesystem
image as MBR partition 2 to the ISO and to use partition offset 16 for
the ISO partition. For a motivation see my proposal to Debian to improve
their bootable ISOs:
https://lists.debian.org/debian-cd/2019/07/msg00007.html
My advise to t2 is to make the ISO ready for both PC-BIOS and EFI by
augmenting the existing xorriso or xorrisofs run for BIOS by new
commands or options as proposed to Debian.
xorriso -as mkisofs:
-partition_offset 16
-append_partition 2 0xef ...path.to.EFI.FAT.image.on.hard.disk...
-e --interval:appended_partition_2:all::
-iso_mbr_part_type 0x83
xorriso native:
-boot_image any partition_offset=16
-append_partition 2 0xef ...path.to.EFI.FAT.image.on.hard.disk...
-boot_image any efi_path=--interval:appended_partition_2:all::
-boot_image any iso_mbr_part_type=0x83
(Is there a web browsable repo of the code which controls the xorriso run ?)
There remains the question what more should be in the EFI FAT image.
Debian ISOs, e.g.
https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-10.1.0-amd64-netinst.iso
and those made by grub-mkrescue for x86_64-efi can give examples.
The FAT images are marked by their partition tables.
Have a nice day :)
Thomas
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