Instructions
Turn on the Nintendo Wii system.
Move the Wii cursor over the Wii icon. Press "A" on the Wii controller to select it.
Locate the icon displayed as a wrench. Move the Wii cursor over it. Press "A" on the Wii controller to select it.
Press the "+" button on the Wii controller two times. Locate "Format System Memory." Move the controller over it. Press "A" to select it. This will automatically downgrade any firmware upgrades you downloaded to the Wii's previous firmware version without HBC.
Press "A" on the controller over "Format" to apply the setting you have selected.