Re: have a mate-desktop CD

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

shirish wrote:
> https://cdimage.debian.org/cdimage/buster_di_alpha2/amd64/iso-cd/debian-buster-DI-alpha2-amd64-xfce-CD-1.iso

Just to be sure that no regression confuses us here, i downloaded that
ISO and let xorriso analyse its boot equipment:

  xorriso -indev debian-buster-DI-alpha2-amd64-xfce-CD-1.iso \
          -report_el_torito plain -report_system_area plain

reports

  El Torito images   :   N  Pltf  B   Emul  Ld_seg  Hdpt  Ldsiz         LBA
  El Torito boot img :   1  BIOS  y   none  0x0000  0x00      4        2011
  El Torito boot img :   2  UEFI  y   none  0x0000  0x00    832        1803

So it can boot from DVD via BIOS and via EFI firmware.

  System area summary: MBR isohybrid cyl-align-on GPT APM

The presence of word "isohybrid" in this line indicates that it can boot
from USB stick via BIOS. The x86 program code in the Master Boot Record
will transfer program execution to the El Torito boot image for BIOS.

  MBR partition table:   N Status  Type        Start       Blocks
  MBR partition      :   1   0x80  0x00            0      1327104
  MBR partition      :   2   0x00  0xef         7212          832

The presence of an MBR partition of type 0xef indicates that it can boot
from USB stick via EFI firmware. The partition table entry marks a range
in the ISO image where a FAT filesystem exists with file /EFI/BOOT/BOOTX64.EFI
which EFI will execute as x86 EFI program.
(32-bit x86 EFI expects and runs /EFI/BOOT/BOOTIA32.EFI.)

So yes, this ISO should boot after being put plainly onto an USB stick
and then offered to BIOS or EFI as boot device.

After booting, /dev/sdX and /dev/sdX1 are both mountable as the ISO 9660
filesystem with nearly all the beef. /dev/sdX2 should be mountable as
FAT filesystem with just the two directories and the one file BOOTX64.EFI.
("X" is the device number which depends on the presence of other devices.)


> I will definitely try rufus in dd mode but as of buy the sticks, make
> sure they are genuine

I'd make that quality check on a GNU/Linux system, where one can rely
that dd does no things that are smarter than wanted:

  dd if=debian-buster-DI-alpha2-amd64-xfce-CD-1.iso bs=1M of=/dev/sdX

Use script check_debian_iso to verify that all written bytes are
correctly readable.

Then overwite the USB stick with zeros
  dd if=/dev/zero bs=1M count=650 of=/dev/sdX
in order to erase the successfully copied ISO.

This verified and then wiped USB stick would be a reliable test bed for
Rufus et.al.

If you finally have success, please provide a short description which
menus or buttons of Rufus need to be used for getting it into DD mode.


Have a nice day :)

Thomas