Things You'll Need
Instructions
Insert the SD card into the computer's SD card slot. Create a new folder in the SD card's root directory and name it "Apps."
Open the computer's Web browser and download the Safe Firmware Updater 4.2.
Unpack the downloaded file with a program such as WinZip, WinRar or Stuffit Expander.
Drag the file contents into the "Apps" folder on the SD card. Eject the SD card from the computer.
Insert the SD card into the Wii's SD card reader and turn on the WIi console.
Click on the Homebrew Channel. Click on "Firmware Updater 4.2" to begin the installation. Allow several seconds for the update to finish.