Does anyone know a reliable source for secret codes, e.g. to change the audio settings and the mic sensibility? Are there any risks applying such codes?

I'm new to this Symbian stuff :)

e-

http://www.allaboutsymbian.com/forum/showthread.php?t=85703
is a good start...

and I am gearing up to taking the plunge:

http://samsungi8910omnia.com/firmware-update-i8910xxig2-audio-codec-fix-released/

*gulp*