why shouldn't you have sd support?
check the softmod any wii guide (link below) you can use the twilight hack for this.
otherwise it is recommended to update to 3.2 at least, 4.1 is just fine to stay on.
simplest method would be to flip in a retail game with 4.1 update on it. should work but if you don't want to risk anything the softmod guide is just fine to get you safely to 4.1 and fully modded.