- just before the 2009.1 release
You mean Pardus 2009.1 RC
- Unable to boot AMD Athlon XP CPUs.
Where is this coming from

(because this would be very strange.)
It's a regular every day CPU.
I forget the exact timeline now, but I think that the RC came out with the problem kernel, and there was then a fairly frantic exchange as it became clear that the problem was on pretty mainstream hardware. If you really want to check it out look for bug 11939
http://bugs.pardus.org.tr/show_bug.cgi?id=11939. In essence the devs produced a number of test kernels to try to isolate the problem (these were only installed by a small number of users [2 or 3 as I recall]) and the version numbers of these were then reused in the actual release and the version that was released re-used the version number of one of the tests that didn't work (and I had left that lying around).