Success Editing Xbox 360 Shaders

He tried editing the shaders of the game 'King Kong' and see if the Xbox 360 would run (allow) it (using the demo on the Kiosk Demo Disc of course as it would be impossible to test this with the retail game that only boots from DVDXBOX(360)):

This game uses vector shaders, compiled with Microsoft D3DX9 Shader Compiler 9.04.91.0000. Both Vector Source and a .Bin files are there. Not that it will lead to anything, but it would be intersting if we can modify the shaders of that game... specially because it is rumoured that high level vector shaders have access tot the system memory as well.

I am trying to figure out 3 things here: 1/ Is it possible at all to mess with the shaders (simple replace blue water by red water) -> has been done as of 30-12-2005

We modified the shaders of the king kong demo. AO created All yellow shaders. Check result. The shaders are compiled run time... so you just can edit script files.
For example, to let it be all white: return float4( 1.0f, 1.0f, 1.0f, 1.0f);
2/ Is it possible, to read from any memory location at all ,using an array overrun -> would really be useful, but i doubt if the gpu has no overrun protection
3/ Is it possible to write to that memory also -> sounds currently too impossible to believe for myself :-)

We need however some assistence on this, as I never have coded shaders before... expert help on this topic would be great. Help out on this XBH thread [please remember - topics in the XBH technical forums are for technical discussion only, not speculation or questions].