A few weeks back Wii dev Crediar mentioned video support and today we can now check out this update. You can run your Gamecube games from the USB for you Wii. See the dev notes about the latest update below.
"Please Note: DM 2.0 is available since an hour ago, the loaders (wiiflow, usbloader) are not yet compatible. Only the latest version of Boot DML (developed by FIX94) is adapted for the moment. Open wiiflow-mod (also developed by FIX94) should follow in time, the last SVN on googlecode Official adding this feature (not yet tested)"
News Source