How to get a cIOS on System Menu 4 with Cboot2
This guide is now out of date!
Use this one here instead.
This is a much simpler way or doing the same thing that the IOS35 trick does, that is = get cIOS249 on your Wii, once you have this you can downgrade your IOS and Wad errors will be a thing of the past. Download this rar and follow these instructions:
1: Copy contents of 'SD Card 1' to SD card.
2: Put card in Wii and go to Data Management > channels > SD Card, then you will get a message saying "Load boot.elf? Select 'Yes'.
3: Install Bootmii v2 as an IOS.
4: Install the Homebrew Channel (unless you have it already)
5: Remove SD card and save the Bootmii installation to your PC.
6: Delete Bootmii installation off of your SD card and copy contents of 'SD Card 2' to your card.
7: Now put card back in, restart your wii ,start HBC, press home then run Bootmii.
8: The screen will be black for 10 seconds then Wad manager will run.
9: Select uninstall first then install IOS249.wad.
10: Go to HB channel and run cIOS38_rev13b-Installer, use network install.
11: Go to HB channel and run IOS downgrader.
12: If you want to stay on 4 download this rar and follow instructions in the readme, but don't run ios downgrader again.
Credit to: Team Twizzers, Wiigator & Waninkoko