Hacking What happens under the hood when we force the video mode in USB loaders?

[sfs76]

Hi

Does anyone know what USB loader GX (or any other loader) does when we choose to force the video mode to launch a game (for example when we set "Force NTSC" on a PAL Wii/vWii)?
Does it (temporarily) modify some global setting in the NAND of the machine or is it just a setting in the RAM?
Since NTSC and PAL have not exactly the same resolution, I was wondering if the changes could be quite complex.

Thanks in advance

 

[The Real Jdbye]

It definitely doesn't modify the NAND. However, I'm not sure if it patches the game itself, or the IOS (since IOS is what interfaces directly with hardware), or if it's taking advantage of a feature already built in to IOS (or cIOS) to change the video mode.