[ipxe-devel] uncompressed (patchable) image?

[Alessandro Salvatori]

actually i hit the very same issues without patching the embedded script
image... seems that the problem is with uncompressed images...

thanks!
-Alessandro-
 Here i am, A young man,
 A crashing computer program,
 Here is a pen, write out my name...

(from: The Servant - Orchestra)



On Tue, Nov 8, 2011 at 14:54, Alessandro Salvatori <sandr8 at gmail.com> wrote:

> the #define COMPRESS 0 seems to do the trick, and after that I can easily
> patch the embedded script.
>
> is there some integrity check? the patched ipxe.iso prints a bunch of
> colored garbage on the console and then reboots. i assume it has a bogus
> bzImage kernel container and that might be doing some checksumming.
>
> the ipxe.dsk instead hangs after emitting "Loading ROM image" and 89
> dots...
>
> i guess if the ipxe.dsk worked, it could be used as an eltorito image for
> an otherwise empty cdrom, hence bypassing any issue with the bzImage
> container in the iso?
>
> thanks!
>
> -Alessandro-
>  Here i am, A young man,
>  A crashing computer program,
>  Here is a pen, write out my name...
>
> (from: The Servant - Orchestra)
>
>
>
> On Tue, Nov 8, 2011 at 03:43, Michael Brown <mbrown at fensystems.co.uk>wrote:
>
>> On Tuesday 08 Nov 2011 10:52:33 Alessandro Salvatori wrote:
>> > would it be easily possible to create non-zbin bootable images (rom,
>> iso,
>> > usb or dsk)?
>> >
>> > i was thinking of having a script as an embedded image, and having
>> > placeholders in it that could be "patched" with the desired values just
>> in
>> > time.
>> >
>> > alas, the compression gets in the way of easily patching the values
>> in...
>> > but the fact that my dsk image takes only 80kB out of 1440 available
>> makes
>> > me wonder if i couldn't do without the compression :-)
>>
>> There's no easily-accessible way to create non-compressed images, but you
>> can
>> try hacking it by setting
>>
>>  #define COMPRESS 0
>>
>> in arch/i386/prefix/libprefix.S.  This code path isn't used very often,
>> and may
>> not be functional.
>>
>> A cleaner solution would probably be to add code to lkrnprefix.S to allow
>> iPXE
>> to pick up and use an initrd image as though it were an embedded image.
>>  There
>> are some complications in doing this, primarily relating to memory
>> allocation.
>> (initrd images are typically placed at the top of memory, which is exactly
>> where iPXE will try to install itself, so there's a good chance that iPXE
>> will
>> overwrite the initrd image.)  This would give you a solution for .iso
>> images
>> (which are based upon .lkrn images); similar schemes could be devised for
>> other image formats.
>>
>> Michael
>>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ipxe.org/pipermail/ipxe-devel/attachments/20111108/166d23c1/attachment.htm>