This is a very great work:
http://www.lyris-lite.net/fu_archives/000601.html (http://www.lyris-lite.net/fu_archives/000601.html)
I never mod my DC with this method, but i will make it in 3 weeks.
Bye Markus
I just did this mod and it works :D
Gotta find a modchip now...
well that's just a soft+hard mode.
Imho the real interesting things is the selectable NTSC-PAL video output :)