If you can see folks on system link but it won't let you join it means the patch isn't working. To get my patch working I did the following.
I used the pig program, Freeboot Tool Maker 2.4 to compile my nand. Basically, do this.
Get your nand using xellous, open the pig tool, select your xbox type & deselect auto detect, enter your cpu key, use the NAND feature under dashlaunch updates, click create custom freeboot, navigate to the freeboot folder & BEFORE you click OKAY, make sure your patch from the dashlaunch zip is in the bin folder of freeboot. THEN click okay.