Interestingly, this update did something odd to my Wii, but only for a few minutes late last night. I had just gotten off the Shop Channel to play a Virtual Console game, then I hopped right back on Shop. It told me to do the update thing and I got all excited about the Internet possibility. I updated and got on shop again. Black screen. And more black screen. No Remote response. Okay. Well I'll just make a sandwich. One sandwich later and... black screen.
So I reset the system and tried again. And again. Black screen. Reset. Um... try ystem update? To my surprise there was one already. I got all excited again, downloaded, and went to the Shop Channel. It was right back to the normal way, just like you guys said. I assumed at the time that they had been trying to do something cool, but messed up and just put the old system files back on for me until they figured it out. So it's possible that you downloaded exactly what you already had. Probably not, but maybe.
Nintendo needs to quality check more before they brick my channels.