1) INSTALLING THE HOMEBREW CHANNEL (HBC) AND BOOTMII
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Note: if this Wii was previously modified, and it has either the HBC, BootMii as Boot2, or a Forwarder Channel installed, you can use that instead of an exploit.
If using BootMii as Boot2 to install the HBC, copy the 'BootMii' folder from your previous BootMii installation to the root of your SD Card (or download it using ModMii). Then boot your wii, BootMii will load, go To the SD menu, load bootmini.elf. This will load the Hackmii Installer allowing you to reinstall the HBC.
If using a Forwarder Channel, just save the boot.elf/dol from the app you want to load (ie. SD:\apps\hackmii_installer\boot.elf or SD:\apps\WiiMod\boot.dol) to the location used by your SPECIFIC Forwarder Channel (ie. SD:\apps\usbloader\boot.dol). Then start the channel and the Hackmii Installer will load allowing you to reinstall the HBC. Note, if your forwarder channel only loads dol's and not elf's, launch WiiMod's boot.dol, then use its "Apploader" to load the Hackmii Installer.
LETTERBOMB EXPLOIT
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REQUIREMENTS: * AN SD or SDHC Card
Go to the "Messageboard" on your Wii and navigate to Yesterday
(depending on your timezone, it could also show up under Today).
Click on the envelope with the pink Bomb icon.
This runs the Hackmii Installer (and silently/automatically installs BootMii as IOS). Use the installer to install the Homebrew Channel (HBC) and Bootmii as Boot2 if possible.
Note: If you get a 'no vulnerable IOS' error message, run ModMii again and this time select the 'Hackmii Solutions' option and follow the new instructions before continuing this guide.
After you exit the hackmii installer, you will be taken to the HBC.
Hit the home button. In the top right corner you will see the IOS used by the HBC.
If the HBC is using an IOS other than IOS58 or your homebrew channel is upside-down, make a note of it as it applies later in the guide (you will have to reinstall the HBC).
If it is using IOS58 and your HBC is not upside-down, you can skip the Reinstall The Homebrew Channel step when you get to it.