"NOTE: DO NOT TRY THIS AT HOME. Without a liable protection against full bricks (like BootMii in boot2), this will render your Wii unusable.
In this video I am purposely breaking my Wii console by installing an IOS 60 stub on firmware 4.0. Because the firmware (and 4.1) runs on the IOS 60, this causes the Wii to freeze on booting up. As a side effect, it caused the Homebrew Launcher to turn upside down when I left the launcher.
Before I did this, I made a full backup of my Wii using BootMii, and because I had BootMii in boot2 (boot2 is basically a place in the Wii that contains code that is executed before the system menu boots up.), I could apply the backup and make my Wii work again."