Wilbrand is an exploit for Wii Message Board (like LetterBomb), which works on Wii Menus 3.0 - 4.3. The tool in the download is operated via the command line, as opposed to a webpage for LetterBomb.
To create the exploit, open a command prompt (cmd)/terminal and go with "cd" to the directory where the Wilbrand binary is (e.g. "cd Downloads"). The MAC address of your Wii is required (can be found under: Wii Button -> System Settings -> Page 2 -> Internet -> Information).
Now enter the following, depending on the operating system. For windows, do
Wilbrand.exe MAC_ADDRESS DATE FIRMWARE STORAGE_LOCATION
For Linux, do
./Wilbrand MAC_ADDRESS DATE FIRMWARE STORAGE_LOCATION
For MAC address, the hyphens can be emitted. The date must be entered in the format MM/DD/YYYY. For location, enter the letter of your SD card (PROTIP: If you enter "C:", Wilbrand will be saved in the current folder!). Example:
Wilbrand.exe 12-34-56-78-90-12 04/29/2014 4.3e G:
Firmware goes from "3.0" to "4.3" with numbers "E" (Europe), "U" (America), "J" (Japan) and "K" (Korea).
The name of this exploit comes from Julius Wilbrand, who discovered TNT in the year 1863. This exploit sometimes is misspelt by the community as "Wiibrand".