Few games not working

So i downgraded my ps3, yesterday and installed the TrueBlue flash, and a true blue dongle..

So far i been able to play from my external drive:

- Fifa 2012
- Infamous 2
- SSX
- Virtual Tennis 4



But there a few games that people claim to be able to play with the regular 3.55 CFW that i cant play...

Gran Turismo 5
God of War 3

When i try to play these two games my PS3 just goes black and i reloads the main ps3 screen..
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actually got god of war to work, had to put a working ps3 disc in, and it worked,also i think to get gran turismo to work i just need to update it