Wii Sd Card Reader

Is it possible to get Wii Homebrew for the 4.0 system firmware?
Unfortunately I updated to 4.0 before I found out about the Wii Homebrew Channel. So, is there any way I could still get it? Or maybe it might be possible to downgrade the firmware version? And also, is there any other things that I can’t do with 4.0 like using a mod chip and other hacks? It would be great if you could list the stuff I would need like an SD card reader, computer, etc.
you can get on 4.0
i did
see the vid and follow the instructions
http://www.youtube.com/watch?v=C79D_wkcAS0
How To Install Homebrew On Your Wii (BannerBomb): The Computer (Part 1)




















