First things first, you're going to need the following:
- A Nintendo Wii, obviously, but make sure it's running System Menu 4.31
- An SD or SDHC card with some free space—it can have other stuff on it.
Step One: Get Your Wii's MAC Address
Before we can do anything, we need to go find your Wii's MAC Address. Go to your Wii's home screen and click the Wii Options button. Once it loads, choose Wii Settings. From there, navigate to the second page and click the Internet button. Finally, click the Console Information button and you'll have your Wii's MAC address. Either write this down or just leave it up on your screen.
Step Two: Generate the LetterBomb.zip File
Now get on your computer and go to please.hackmii.com and enter your Wii's MAC address. You'll also need to type in what you see in the captcha image. Once you've filled those things out, cut the red or the blue wire. It doesn't really matter. This will generate a LetterBomb.zip file that will start downloading.
Step Three: Prepare the SD Card
Now insert your SD or SDHC card into your computer, because we're going to need to copy some files onto it. First, unzip the LetterBomb.zip file on your computer. Next, drag the contents of the zip to your SD or SDHC card. When it's done copying, eject it, and put it in your Wii.
Step Four: Open the LetterBomb
Back on the Wii, head on over to the Wii Message Center. There's going to be a new message for you with a bomb in it, but where that message is going to be will depend on your time zone and when you generated the file. In most cases, it will be in yesterday's mail, but it could be today or a couple of days ago. You'll know when you see it. When you're ready to pull the trigger, just click on the LetterBomb message icon. The process will take about a minute, so be patient. You'll have a hacked Wii when it's done.
If you run into any issues along the way it's probably because you don't have the right version of the Wii System Menu. If you try to use LetterBomb with the wrong version, it'll freeze your Wii. Not to worry—just force-reboot your Wii, make sure you update properly, and try again. Obviously you want to do the update beforehand, but in the event you forget it's not really a big deal.
Step Five: Install BootMii and the Homebrew Channel
Once LetterBomb has done its thing, it'll tell you to press 1 to continue. Do that and you'll be able to use your WiiMote to start installing things. What you're really interested in is the Homebrew Channel, but BootMii will provide you with some extra features (like backup). Once everything is installed, you'll be all set.