Arch Linux

scdbackup

Member

Registered: 2013-05-30

Posts: 73

Re: BIOS-only computers and ArchISO

Hi,

i don't see any reason why this DVD should not be recognized by BIOS as
bootable. I.e. i am clueless for now.

At least the removal of the partition tables and the MBR worked as expected.
Thus the ISO lost the capability to boot from USB stick.

Have a nice day

Thomas

N.T.

Member

Registered: 2021-03-01

Posts: 27

Re: BIOS-only computers and ArchISO

Thomas, thank you very much for wanting to help! Have a nice day...

scdbackup

Member

Registered: 2013-05-30

Posts: 73

Re: BIOS-only computers and ArchISO

Hi,

next experiment proposal:

What happens if the ISO gets packed up with only the most oldfashioned
boot lure, which is BIOS-only from optical media only ?
(2008, before H. Peter Anvin introduced the first isohybrid script.)

# Choose a mount point that is suitable for your system
mount_point=/mnt/iso

# Mount the "Test 2" ISO which does not boot
sudo mount archlinux-2022.11.02-x86_64.iso "$mount_point"

# Pack up the test ISO the old way
xorriso -as mkisofs \
  -o test.iso \
  -V ARCH_202211 \
  -c /syslinux/boot.cat \
  -b /syslinux/isolinux.bin \
  -no-emul-boot -boot-load-size 4 -boot-info-table \
  "$mount_point"

# Unmount the original ISO
sudo umount "$mount_point"

Then check whether all EFI and partition stuff is missing in test.iso:

xorriso -indev test.iso -report_el_torito plain -report_system_area plain

should report (modulo xorriso version and free space on disk):

GNU xorriso 1.5.5 : RockRidge filesystem manipulator, libburnia project.

xorriso : NOTE : Loading ISO image tree from LBA 0
xorriso : UPDATE :     107 nodes read in 1 seconds
xorriso : NOTE : Detected El-Torito boot information which currently is set to be discarded
Drive current: -indev 'test.iso'
Media current: stdio file, overwriteable
Media status : is written , is appendable
Boot record  : El Torito
Media summary: 1 session, 392589 data blocks,  767m data,  343g free
Volume id    : 'ARCH_202211'
El Torito catalog  : 40  1
El Torito cat path : /syslinux/boot.cat
El Torito images   :   N  Pltf  B   Emul  Ld_seg  Hdpt  Ldsiz         LBA
El Torito boot img :   1  BIOS  y   none  0x0000  0x00      4          41
El Torito img path :   1  /syslinux/isolinux.bin
El Torito img opts :   1  boot-info-table isohybrid-suitable
xorriso : NOTE : No System Area was loaded

Then try whether test.iso boots from DVD.

Have a nice day

Thomas

N.T.

Member

Registered: 2021-03-01

Posts: 27

Re: BIOS-only computers and ArchISO

Hi!

What happens if the ISO gets packed up with only the most oldfashioned
boot lure, which is BIOS-only from optical media only ?
(2008, before H. Peter Anvin introduced the first isohybrid script.)

Sorry, I think we're going in the wrong direction.
The fresh (2022-10-21) Arch-based SYSTEM RESCUE CD works fine for me.
The boot loader screen for me: https://i0.wp.com/9to5linux.com/wp-cont … ecd618.jpg .
The boot loader screen for UEFI machine: https://i0.wp.com/9to5linux.com/wp-cont … d618-2.jpg .
There are some ArchISO patches: https://gitlab.com/systemrescue/systemr … in/patches .

scdbackup

Member

Registered: 2013-05-30

Posts: 73

Re: BIOS-only computers and ArchISO

Hi,

Sorry, I think we're going in the wrong direction.

The purpose of my proposals is to find out what spoils the relation
between your machine's BIOS and the ISO.

Up to now we know that the BIOS does not step over the limits of tradition
by (mis-)interpreting MBR or partition table on an optical medium.

The next suspect to exclude (or not) is the UEFI boot image.
Thus my proposal to repack the ISO to be BIOS-only and DVD-only.

Have a nice day

Thomas

N.T.

Member

Registered: 2021-03-01

Posts: 27

Re: BIOS-only computers and ArchISO

Thus my proposal to repack the ISO to be BIOS-only and DVD-only.

Reporting...
It's working!

scdbackup

Member

Registered: 2013-05-30

Posts: 73

Re: BIOS-only computers and ArchISO

Hi,

ok, now we know that it's not about the ISOLINUX files in the ISO.

Further, you now probably have a way to make the newer Arch ISOs bootable
on your machine.

-------------------------------------------------------------------------

This would be the way to reduce it to BIOS-only and to put it onto an
optical medium in /dev/sr0 without the need for an intermediate ISO image:

mount_point=/mnt/iso
original_iso=archlinux-2022.11.02-x86_64.iso
volume_id=ARCH_202211
burner=/dev/sr0

sudo mount "$original_iso" "$mount_point"

xorriso \
  -outdev "$burner" -blank as_needed \
  -as mkisofs \
    -V "$volume_id" \
    -c /syslinux/boot.cat \
    -b /syslinux/isolinux.bin \
    -no-emul-boot -boot-load-size 4 -boot-info-table \
    "$mount_point" \
  -- \
  -pacifier xorriso

sudo umount "$mount_point"

The DVD+RW will get pseudo-blanked by writing a few zeros, so that a new
first ISO session can be written.
The arguments are a mix of xorriso's native commands and the mkisofs
emulation options, which get terminated by the argument "--".
The last two arguments are the native xorriso command and the parameter
which re-enables xorriso's native pacifier behavior, after the emulation
enabled the mkisofs-ish pacifier. Expect to see every second such a line:

xorriso : UPDATE : Writing:     149120s   38.0%   fifo 100%  buf  99%    4.0xD 

Above depends on ISOLINUX being the boot loader for BIOS.
When GRUB takes over that role, the -as mkisofs part will probably have
to look like:

    -V "$volume_id" \
    -c /boot.catalog \
    -b /boot/grub/i386-pc/eltorito.img \
    -no-emul-boot -boot-load-size 4 -boot-info-table --grub2-boot-info \
    "$mount_point" \

These options where derived from
  https://pkgbuild.com/~tpowa/archboot/is … x86_64.iso
which already has GRUB for BIOS. Names might change, though.

-------------------------------------------------------------------------

Back to research.
Let's try whether the UEFI boot image spoils the party.

mount_point=/mnt/iso
volume_id=ARCH_202211
burner=/dev/sr0
# Would work too:
# burner=test.iso

# (The dd iskip= and size= numbers will work only with the "Test 2" ISO.)
sudo mount archlinux-2022.11.02-x86_64.iso "$mount_point"

# The EFI boot image is not a file in the original ISO. We extract it and
# later put it into the new ISO.
dd if=archlinux-2022.11.02-x86_64.iso bs=512 skip=1570816 count=67584 \
   of=/tmp/efi.img

xorriso \
  -outdev "$burner" -blank as_needed \
  -as mkisofs \
    -V "$volume_id" \
    -c /syslinux/boot.cat \
    -b /syslinux/isolinux.bin \
    -no-emul-boot -boot-load-size 4 -boot-info-table \
    -eltorito-alt-boot \
    -e /efi.img \
    -no-emul-boot \
    "$mount_point" \
    -graft-points \
    /efi.img=/tmp/efi.img \
    --sort-weight 2 /syslinux/isolinux.bin \
    --sort-weight 1 /efi.img \
  -- \
  -pacifier xorriso

sudo umount "$mount_point"

rm /tmp/efi.img

(The --sort-weight options pin the BIOS image to a storage location before
the UEFI image. Partly cargo cult, but widely customary.)

Inspection of the DVD by:

xorriso -indev "$burner -report_el_torito plain -report_system_area plain

should yield:

GNU xorriso 1.5.5 : RockRidge filesystem manipulator, libburnia project.

xorriso : NOTE : Loading ISO image tree from LBA 0
xorriso : UPDATE :     108 nodes read in 1 seconds
xorriso : NOTE : Detected El-Torito boot information which currently is set to be discarded
Drive current: -indev '/dev/sr0'
Media current: DVD+RW
Media status : is written , is appendable
Boot record  : El Torito
Media summary: 1 session, 409485 data blocks,  800m data, 3683m free
Volume id    : 'ARCH_202211'
El Torito catalog  : 40  1
El Torito cat path : /syslinux/boot.cat
El Torito images   :   N  Pltf  B   Emul  Ld_seg  Hdpt  Ldsiz         LBA
El Torito boot img :   1  BIOS  y   none  0x0000  0x00      4          41
El Torito boot img :   2  UEFI  y   none  0x0000  0x00      0          60
El Torito img path :   1  /syslinux/isolinux.bin
El Torito img opts :   1  boot-info-table isohybrid-suitable
El Torito img path :   2  /efi.img
xorriso : NOTE : No System Area was loaded

Have a nice day

Thomas

N.T.

Member

Registered: 2021-03-01

Posts: 27

Re: BIOS-only computers and ArchISO

Further, you now probably have a way to make the newer Arch ISOs bootable on your machine.

Will I have to do it myself every time now?

Back to research.

This also works as expected.

scdbackup

Member

Registered: 2013-05-30

Posts: 73

Re: BIOS-only computers and ArchISO

Hi,

Will I have to do it myself every time now?

It would be your fallback, if it works reliably at all.

[The ISO with BIOS and EFI images] also works as expected.

But it should not. Grrr.

It offers about the same boot equipment as the partly zeroized ISO about
which you report failure in
  https://bbs.archlinux.org/viewtopic.php?id=280876#23
You reported xorriso's assessment of the non-functional state in
  https://bbs.archlinux.org/viewtopic.php?id=280876#25

The only difference which i see towards the working BIOS+EFI ISO is
the storage location of the EFI boot image.
The "Test 2" ISO has it at 2048-byte-block 392704, the youngest experiment
has it at block 60. But the working "Test 1" ISO has the EFI image at
block 389632.

The problem of being ignored as boot medium appears to be very volatile.

It seems less plausible that the BIOS would not accept boot images which
are at particular storage locations and accept others which are quite
near to the failing locations.
More plausible is the suspicion that the burnt DVDs sometimes are readable
for the BIOS and sometimes are not.

So i wonder:

How old is the burner drive and the DVD+RW medium ?
Did you try more than one medium with an ISO which does not boot ?

After a DVD failed to boot, does xorriso still recognize the boot equipment
if you let Debian boot and run without removing the failed DVD:

xorriso -indev /dev/sr0 -report_el_torito plain -report_system_area plain

?
(I assume that there is only one DVD drive and thus /dev/sr0 is its device
file.)

Have a nice day

Thomas

N.T.

Member

Registered: 2021-03-01

Posts: 27

Re: BIOS-only computers and ArchISO

But it should not. Grrr.

Ahahaha... 

All the equipment is old and problems with it are not excluded. I am afraid that it will not withstand a long test. 
So I suggest waiting for confirmation or denial of such cases from other users. And then we will continue.

Thank you for your time!
Have a good day and night...