Word has been flying around the internet about a disc someone found in there Wii when it was returned after being repaired. The disc is supposedly used to backup data from the Wii and access the Bios.
So far all that has been released are images of the disc. And pictures of the supposed disc running on the Wii.
The actual disc ISO has yet to be released. Due to WiiDev keeping it to themselves for the time being.
More on the subject at tehskeen.