This tutorial will help you fix your Wii from a Banner Brick, which occurs when a user installs a channel with an invalid banner, and usually gives a black screen, freeze after the Health & Safety screen, or display "The system files are corrupted" error.
Instructions
Requirements An SD card or USB drive
If you do not have Priiloader installed: A PC with Linux installed, or a Raspberry Pi since it most likely has Linux installed already
YAWM ModMii Edition
Section I - Entering HBC (Priiloader)
You can enter Priiloader in this state by holding RESET on the console while turning it on.
If you do not have Priiloader, scroll down to If you do not have Priiloader: below If you do not have Priiloader: Follow this guide until step 13, then come back here. Ensure you do not press A on the Health and Safety screen.
Once you are in the HackMii installer, exit it, you should now be in the HBC, continue to Section II After that, you should be on a screen like the image below.
Section I - Entering HBC (Priiloader)
If you are on Wii U in the Aroma environment, you can load the Wii U forwarder on your Wii U Menu.
If you don't have the Priiloader Wii U Forwarder, you can get it here.
If you have not yet installed Aroma, here is a guide to do so.
If you do not have Priiloader, scroll down to If you do not have Priiloader: below If you do not have Priiloader: Place the file you downloaded for your environment in wiiu/apps
Open it and you should be taken to the HBC, once it does, continue to Section II After that, you should be on a screen like the image below.
Section II - Uninstalling WADs
Select YAWM ModMii Edition from the list of homebrew.
Select your source device.
Press A , then press A again on your WAD.
Press D-Pad Right to change the selected action from Install WAD to Uninstall WAD, then press A .
If you've installed multiple WADs, do this for every WAD you have installed. Once it's uninstalled, Press A to go back, then press Home to return to HBC. In HBC, press Home again, and then Return to System Menu .
Your Wii should now be unbricked, please don't install that WAD(s) again.
