I found a way to unbrick my wii.
1. Held reset button to launch preloader.
2. Launched Homebrew Launcher as boot.dol from root of SD card (launching homebrew channel or cIOS Downgrader wouldn't work).
3. Run cIOS Downgrader 1.2 from Launcher. (You may need cIOS beforehand, I did but I'm not sure it's neccesary)
4. Downgrade to SysMenu 2.2U
5. Reupgrade to 4.0 using Waninkoko's Installer
6. Reinstall cIOS, DVDX, cIOS_usb2, cIOS-CORP, cios60BF, and StarPatch. Not Preloader again!
7. Function as normal. - Twil