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Re: Thanks Thomas!



Hi,

i wrote:
> > (It would be embarrassing if a different Thomas was meant.)

songbird wrote:
>   context is good...  i dislike posting last names to usenet/mailing lists.

Well, germany is full of baby-boomer Thomases. :))


> >   http://www.ludd.ltu.se/~ams/tmp/isohdpfx.bin.170324

> i hope the author released it as open source/bytes!  :)

The bug fix is not worth an own copyright.
So it is provided under the BSD-ish license of isohdpfx.S by H. Peter
Anvin and Intel Corporation:
  http://git.zytor.com/syslinux/syslinux.git/tree/mbr/isohdpfx.S


> i'm not sure what else i can do.

Nothing more for now. We have to wait for a decision of debian-cd
how to handle this not-so-exotic-any-more bug.


>   ok, looks like the two versions are the same in
> the first sector (netinst for i386 and amd64) so
> the fix should work...

The fix should apply to all Debian i386 and amd64 ISOs which were made
with isohybrid functionality. The bug was introduced in may 2009. Steve
McIntyre announced the new capability of Debian testing ISOs in january
2011. Debian 6 came out in february.
I have a debian-6.0.5-amd64-businesscard.iso which already is isohybrid.

One possible drawback is that it does not preserve the Apple Partition
Map of the EFI-capable Debian ISOs.
I am not aware of any machine which would boot Debian ISOs with APM
and would not if APM is missing. To my understanding it is necessary
to anounce HFS+ boot images to certain old Macs. But Debian ISOs do
not provide HFS+ images.


> diff new amd
> < 0000000   3 355 220 220 220 220 220 220 220 220 220 220 220 220 220 220
> < 0000020 220 220 220 220 220 220 220 220 220 220 220 220 220 220 220 220
> ---
> > 0000000   E   R  \b  \0  \0  \0 220 220  \0  \0  \0  \0  \0  \0  \0  \0
> > 0000020  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0  \0

Upper without APM signature, lower with APM signature.
Both groups of 32 bytes are supposed to do nothing harmful when executed
as x86 machine code (which PC-BIOS does).

The other differences are due to the new instructions of the fixed version.
They change positions of older instructions and cause changes in relative
memory addresses.


Have a nice day :)

Thomas


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