Bad news, folks.
I installed the update yesterday and now the SD Media Launcher disc won't boot. Looks like Nintendo are really cracking down, even on legal homebrew.
So whatever you do, if you want homebrew on your Wii via SD Media Launcher, DO NOT UPDATE YOUR FIRMWARE!
DIGG THIS NEWS AND STOP PEOPLE UPDATING
UPDATE - PETERM Has released the worlds first port of Quake to the Gamecube and Nintendo Wii, full details Here