The link is not dead.
It's still on the first page of this forum:
http://gbatemp.net/forums/wii-hacking.108/
thread name : Wii USB Port1.
To explain briefly :
You need a cIOS compatible with port1, and only 4 cIOS are working for Wii games:
- Hermes cIOS v4
- Hermes cIOS v5 (and 5.1)
- d2x cIOS v9 (beta)
- d2x cIOS v10-alt (beta53)
If you want port1 for additional controllers (microphones, wiispeak, etc.), then you need a cIOS based on IOS58.
If you want Gamecube games, then you don't need cIOS at all, but both ports are working but with restrictions.
DIOS MIOS : Either port0 OR port1, if you plug both then games must be on port0
Devolution: As it's based on IOS58, I suppose the default port is Port1, so if you plug both then put games on port1. (I didn't test it, maybe it works on either port).