I am running an older HP ZT1260 laptop. I upgraded to 1GB ram, 80GB hard drive. With Windows XP Pro.,all Windows updates, as well as all the HP updates for this machine (including the BIOS 1.05 Update) Recently I removed the SL6EX 1.6 GHz wo/SpeedStep CPU and installed a SL6FK 2.0 GHz w/SpeedStep CPU. I had a terrible time with the SpeedStep not working properly and freezing the machine and so on. It was so bad that I removed the 2.0 and reinstalled the 1.6. This last weekend I decided to try the 2.0 once again, and once again all the same problems. I left the 2.0 in and this morning I flashed the BIOS again with the same flash (1.05) I used before, and now the SpeedStep is working as it should? Does this make any sense? My thought was that the BIOS during flash would see the new processor and adjust to it, is this right or just a serendipity?

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Did you use a freshly downloaded copy-- or the same exact file as before (for the flash)?
It should not make a difference...but if it's working now-- I would not argue.
As far as I know-- a bios is not seeing anything during a flash... but perhaps one tiny setting was reset the second time-- that's an old BIOS, too-- circa 2002-- ?

Fresh download of same file dated 09-2002.

While BIOS is pretty simple code--It may be possible that there was a minor corruption-- during the first download.
I don't code -- so I can't say for sure--but perhaps just enough so it would still boot- but not quite function correctly... then the reflash fixed it.