RE: remastering ISOs to append boot options
Hi chaps,
The method Klaus outlined is the method we used to add all of the serial
braille and language choices to the Vinux CD. This requires that a user
enters the correct cheatcode if they want a specific serial braille display
or language. If no cheatcode is entered then a USB braille display and EN is
used as the language. I use Isomaster to do this, but I have increased the
size of the isolinux.cfg file considerably (maybe by 20x) and it caused no
problems as yet. Not sure why. However it seems from your original post that
you don't want cheatcodes at the boot prompt, but just a default setting for
a particular braille device and language which could be done by simply
editing the first default entry in the isolinux.cfg. This would allow to use
the chosen braille display and language on the live CD. Presumably once it
was installed to a hard drive you could save these settings. Not sure if this
helps or not.
drbongo
-----Original Message-----
From: Klaus Knopper [mailto:accessibility@knopper.net]
Sent: Mon 06/07/2009 18:52
To: Joseph Rawson
Cc: debian-accessibility@lists.debian.org; debian-devel@lists.debian.org
Subject: Re: remastering ISOs to append boot options
Hello,
On Mon, Jul 06, 2009 at 10:46:01AM -0500, Joseph Rawson wrote:
> On Sunday 05 July 2009 19:42:19 Samuel Thibault wrote:
> > Hello,
> >
> > Some a11y people asked how to very easily remaster ISOs so as to append
> > parameters to the kernel command line, to e.g. setup the braille
> > configuration once for good before burning a CD. I've prepared a small
> > crude script to do that on
> >
> > http://people.debian.org/~sthibault/remaster-append.sh
> >
> > it depends on the bsdtar and genisoimage packages, sample use is
> >
> > remaster-append.sh "brltty=eu,ttyS-1,fr_FR"
> > debian-testing-i386-businesscard.iso myimage.iso
An easier way (for the non-iso-expert user) would be modifying the .iso
file directly by exchanging content inside the isolinux.cfg file with no
size change, using a script or program. We have done this in Knoppix a
while ago, in order to modify boot options right before burning the iso,
without the need to remaster, when we first only provided the german
versions of the image.
Ann (ancient) C program for modifying el torito floppy emulation
bootable iso9660 filesystem images can be found here:
http://ftp.uni-kl.de/pub/linux/knoppix/knoppix-customize/
Modern distros use "no emulation" boot, which is actually easier to
handle than the floppy-based method. The C program could be rewritten in
order to handle this, but personally, I think that a simple shell script
using sed or perl would suffice.
[Start of] discussion:
Changes to isolinux.cfg inside a .iso image must not
exceed or even change the space allocated by the file
inside the image. Therefore, dummy lines (comments)
could be used to pre-allocate space in isolinux.cfg, so
that it is possible to actually ADD stuff without having to overwrite
existing lines.
Advantage: You don't need additional space. With a pipe-mode script, you
can even feed the resulting image directly into cdrecord/wodim, so that
no writable disk or ram space is needed at all for intermediate steps.
Size and content as well as all file locations in the iso file remain
as they are.
Disadvantage: Space for changes is limited by the original isolinux.cfg
size, no files can be added, the method is only changing existing files.
Regards
-Klaus Knopper
--
To UNSUBSCRIBE, email to debian-accessibility-REQUEST@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
Reply to: