These instructions will assume you're using an SD card to mod your Wii with, but you can use a USB storage device instead. However, the exploit LetterBomb requires a SD card due to how the Wii Message Board works.
Have a Wii mini and not afraid to mess with Bluetooth and Linux? [Check out Bluebomb](https://forum.wii-homebrew.com/index.php/Thread/59342-Installing-Homebrew-on-the-Wii-Mini/).