Well there is a small ray of hope for you recovering your dead player. There are plenty of different versions of firmware in our download section. You could try downloading and flashing all the 9.0.50's one at a time until you find one that works. ( i don't think theres many though)
The alternative is trying a new tool thats in beta right now called s1flash.
It doesn't support 9.0.50...yet... but it might be worth a try.. you can download it at
www.s1mp3.de