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Re: UEFI support for mini.iso?


Wouter Verhelst wrote:
> http://anonscm.debian.org/cgit/d-i/debian-installer.git/tree/build/util/geniso_hybrid_plus_firmware_partition
> I add a line isohybrid -u "$iso"

This last isohybrid run replaces the partition which was crafted
by the fdisk run.

This is also the reason why fdisk does not succeed with the result of
isohybrid -u. Partition 2 cannot be created because ist already exists.

If the script would contain the ISO production run, then i would
propose xorrisofs options like -isohybrid-gpt-basdat and
-append_partition which would make runs isohybrid and fdisk unneeded.

But since there is only the partition maker to see, i propose to just
change partition number 2 to 3 in the fdisk run and to let it happen
after the isohybrid -u run.

I tested this with a result of isohybrid -u named mini-test.iso:

- Because isohybrid -u expanded partition 1 to the end of the image
  file, i had to add once again bytes for the "Firmware Partition"
  like the script does in line 37 by
     cat "$firmware_volume_file" >> "$iso"
  My command was
     dd if=/dev/zero count=12288 >>mini-test.iso

  This waste is not necessary if the isohybrid -u run happens before
  the cat "$firmware_volume_file" >> "$iso" run.

- Then i ran /sbin/fdisk with nearly the same input as in the script
  but with partition number 3 instead of 2:
    # Make new partition #3
    echo n
    echo p
    echo 3
    echo # use default start sector

    # Pedantically, set partition type to 1: FAT 16
    echo t
    echo 3
    echo 1

    # Done!
    echo w

/sbin/fdisk -lu reports about the result:

  Device         Boot Start   End Sectors  Size Id Type
  mini-test.iso1 *        0 63487   63488   31M  0 Empty
  mini-test.iso2        240  1071     832  416K ef EFI (FAT-12/16/32)
  mini-test.iso3      63488 75775   12288    6M  1 FAT12

This boots by

  qemu-system-x86_64 -enable-kvm -m 512 -bios /usr/share/ovmf/OVMF.fd -hda mini-test.iso

Have a nice day :)


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