I have not tried to update the firmware on my K10, as I know it will fail. Yes I am a pessimist.
I think that all camera manufactures should provide an up date service free of charge, if they change the firmware.Because if was correct from the start, updates would not be necessary.

I purchased my first Pentax SLR camera back in 1974, a Spotmatic II, I still have this camera and it is still in perfect working condition (one service only). The light meter on this camera is very accurate. So when it was time to upgrade to a digital SLR, the choice was very simple, a K10D. I have had this camera now for approx sixteen months. But I am very disappointed with the light meter in this camera, manual adjustment
necessary before or after nearly every exposure. I also have a Canon Power Shot 640 compact. The light meter on this camera out performs the K10D, by a factor of ten. Anyone's guess which make of camera I will go for if I upgrade again, even though it will mean buying another ste of lens.