iso2flash img

Thomas Schmitt scdbackup at gmx.net
Thu Mar 22 16:41:53 UTC 2012


Hi,

Vitaly Magerya <vmagerya at gmail.com>:
> > you might want to try to dd the iso image directly onto USB instead; there
> > where talks that Ubuntu would support this starting at 11.10.

Da Rock <freebsd-hackers at herveybayaustralia.com.au>:
> Nada. Tried that and it didn't work. I'm not sure how that would work given
> that it uses isolinux to boot- ergo needs a cd to load the kernel. Maybe
> some way to determine the install media?

The trick is called "isohybrid".
It works by a DOS MBR which starts the same executable boot image
that is pointed to by the El Torito boot catalog.
If the ISO is on a hard disk (or alike), then the BIOS boots via MBR.
If it is on an optical medium, then the BIOS boots via El Torito.


The question is rather why it does not work for you.

I downloaded
  ubuntu-11.10-desktop-i386.iso
from
  http://www.ubuntu.com/download/ubuntu/download
and put it onto an USB stick (by a Linux machine, but that should not matter)
  dd of=/dev/sdc if=ubuntu-11.10-desktop-i386.iso bs=2048
Note that /dev/sdc is not the first partition but the whole USB stick.

This stick boots on amd64 hardware.
After some waiting with sparse iconography i get to the question
whether i want to try or to install. I choose to try and get a
graphical desktop. From the icon list i start Firefox and google
a bit via my internet router. All seems well.


On FreeBSD, GEOM complains about the DOS partition alignment.
Partition 1 starts at block 64.
  fdisk -p /dev/da0
  # /dev/da0
  g c243 h255 s63
  p 1 0x17 64 1423896
  a 1
Nevertheless these two commands work and open access to the image content:
  mount -t cd9660 /dev/da0 /mnt
  mount -t cd9660 /dev/da0s1 /mnt
(The ISO has two superblocks and two directory trees.)


Does your hardware boot from USB stick at all ?
Is its firmware (U)EFI rather than BIOS ?


Have a nice day :)

Thomas



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