Bannerbomb is currently the most popular exploit for hacking your Wii (4.2 and lower). This is mainly because its the only exploit that can be launched from the wii menu itself, without having to buy a certain game.
It uses a malformed banner to cause a buffer overflow (as it fails to load the malformed banner, similar to a banner brick). Like this, it can load any boot.dol or boot.elf file that can be found in the root of the SD card.
If a boot.elf and a boot.dol are in the SD card root at the same time, Bannerbomb will fail to load.
The system menu 4.2 update blocked the old version of Bannerbomb. A new version was made that uses the same exploit, but on another place (the SD card menu that was added in update 4.0).
Since the new bannerbomb will only work with the SD card menu, it can only be used on System menu 4.0 and higher.
Note: The author of bannerbomb does not like it when other people mirror his links. Please link to the bannerbomb site instead.
1. Go to the bannerbomb website (use the second link if you have System menu 4.2 and the other link for all the older versions). You will see some steps there, which you are free to follow, as this guide basically tells you the same.
2. First of all, we need to rename our private folder (this is because bannerbomb can only work if its the only file in the private folder). You can for example rename it to "privateold" or something similar. Of course you can also move the private folder to another place.
3. Download the first version of bannerbomb (aad1f_v108.zip for 4.1 and lower, abd6a_v200.zip for 4.2). Extract the zip file to the root of the SD card. You should have a private folder again, with only bannerbomb in it.
4. Download any wii app and place its .dol or .elf in the root of the SD card. Be sure to rename it to boot.dol/.elf
5. If you enabled WiiConnect24, go to your Wii settings and disable it. This increases the chance for success (due a bug in bannerbomb)
6. Now we need to execute the bannerbomb exploit.
7. After step 6, there are 2 things that can happen.
Additional Hackmii installer steps:
8. You will see a Scam warning screen.
Wait for the message at the bottom to appear, then press 1.
9. You will see a screen like this one:
Depending on your wii, it will show different things behind BootMii:.
Now we get to the main menu, where we can install everything.
First install the Homebrew Channel (choose Yes, continue).
The Homebrew Channel will now be installed on your Wii.
Optional (Recommended) Steps: Installing BootMii
BootMii is a helps greatly with Brick protection and it is recommended to install it.
It is not required however.
These steps don't work on WiiU
10. In the HackMii main menu, choose BootMii... and press A. You will get another menu.
11. Before BootMii will work, we need to prepare our SD card, so do that first with the third option.
12. Install BootMii as IOS. This will always work.
13. If you're one of the lucky winners, choose install Bootmii as Boot2, then Yes, continue and let it install.
Once you're done, return to the Main menu and choose Exit. It will reboot the Wii.
If you installed BootMii as Boot2, the BootMii menu will appear every time.
14. Now you have to delete bannerbomb of the SD card! (just delete the "atkn" folder inside private/wii/title/).
Don't forget to restore your old private folder if you had one!
So, was that it?
It mostly depends on what you want to do. Many Wii applications will already work for you now.
However, if you want more, like backup loading, custom themes, etc; you will need to continue below.