This is the ULTIMATE Tutorial for everything you need for System Menu 4.1
for EUR and USA Wiis only not JAP or KOREAN

There are two methods described in this guide. Online and completely Offline installations. The Online installation is the safer method. They should both work on ANY Wii besides LU64+. You only need to use one guide, they both do the same thing. Please read the entire thread including FAQ before asking a question.

please take note every1 i didnt write this guide i found it and thought more people could use it so here you go credits to asssassda for writing the guide
i have used this myself and can confirm that it works i used the online version if you have wifi i recomend that you use that 1 to
i did reupload the links so they are my own appart from 1
please at least give a thanks to keep this thread current so more people see it and get the chance to mod thier wii and save some

Online Downgrade/Upgrade

Prerequisites:
–SD card
–Wifi Connection (Ethernet doesnt work)
–Unplug any Gamecube Memory Cards, Gamecube Controllers, USB Devices
–Read the FAQ and be prepared with a general knowledge of Wii Homebrew

1) Format your SD card to FAT16. Copy the contents inside the sd folder to the root of your SD card

If you have bootmii with a nand backup, the homebrew channel, and cios installed already you may skip to step 8

2) Insert the SD card in the Wii and go to Data Management>Channels>SD Card press YES on the dialog box that asks to load boot.dol

3) Install the Homebrew Channel and install BootMii as boot2 if possible or as an IOS if boot2 is not available.

4) Launch Bootmii (if you installed to boot2 just reset the system if you installed to IOS go to the HBC and press the Home button)

5) Open the config menu (gears) and choose backup NAND (green arrow) wait for it to finish and restart the Wii

6) Run Trucha Bug Restorer and choose "IOS36" and pick "Downgrade IOS15" and "Download IOS from NUS" then restart

7) Run Trucha Bug Restorer again and choose "IOS15" then "IOS36 menu" set "IOS to slot 36" and "yes" "yes" "yes" to the 3 options then press "Install patched IOS36" and "Download IOS from NUS"

Install cIOS36 rev10 to IOS249 using Network install mode

9) Downgrade system IOS files using IOS Downgrader

10) Downgrade to 3.2 using cIOS Downgrader even if you are already on 3.2 run this

11) Run 4.1 Firmware-Updater.

12) Using Dop-IOS install IOS60 v6174 with Sig Hash Check.

13) Install preloader. On the install screen press 1

14) Set your preloader settings. In preloader hacks enable "Skip disc update check"

———————————————————————

Offline Downgrade/Upgrade

Prerequisites:
–SD card
–Unplug any Gamecube Memory Cards, Gamecube Controllers, USB Devices
–Read the FAQ and be prepared with a general knowledge of Wii Homebrew

This package contains instructions on how to acquire the necessary files from Nintendo to do an offline update
This package will work on ANY Wii! Virgin or Nintendo Official Updated without cios!!

1) Extract the files somewhere on your hard drive such as C:wii and run prepare.bat and choose your desired version

2) Check that the WAD files are correct with MooSFV. If any files are not correct run clean.bat and start over

3) Format your SD card to FAT16. Copy the contents inside the sd folder to the root of your SD card

If you have bootmii with a nand backup, the homebrew channel, and cios installed already you may skip to step 10

4) Insert the SD card in the Wii and go to Data Management>Channels>SD Card press YES on the dialog box that asks to load boot.dol

5) Install the Homebrew Channel and install BootMii as boot2 if possible or as an IOS if boot2 is not available.

6) Launch Bootmii (if you installed to boot2 just reset the system if you installed to IOS go to the HBC and press the Home button)

7) Open the config menu (gears) and choose backup NAND (green arrow) wait for it to finish and restart the Wii

Run Trucha Bug Restorer and choose "IOS36" and pick "Downgrade IOS15" and "Load IOS from sd card" then restart

9) Run Trucha Bug Restorer again and choose "IOS15" then "IOS36 menu" set "IOS to slot 36" and "yes" "yes" "yes" to the 3 options then press "Install patched IOS36" and "Load IOS from sd card"

10) Run cIOS36_rev10-Installer and choose WAD Installation

11) Run WAD-Manager_v1.4 again. Choose IOS249 and install WADs 01-18. If WAD Manager freezes during installation just try again from the WAD it froze on.

12) While still in WAD Manager install SystemMenuv###.wad

13) It is highly recommended that you install preloader to prevent bricks. On the install screen press 1

14) Hold reset while powering on to access preloader and set preloader settings. In preloader hacks enable "Skip disc update check"

———————————————————————

You can now use Backup Loaders and run Virtual Console and WiiWare from the SD Channel!

I recommend Backup Launcher NeoGamma for Wii Backups

If you want Gamecube backups install the custom MIOS and use Gamecube Backup Launcher 0.2

You can also now install a USB Loader. I reccomend USB Loader GX

If you want to load games from the disc channel you must install CIOSCORP
The following section applies to both Online and Offline installations.

NOTE: NO ASKING FOR LINKS TO CIOS WADS
This section has some risks and is OPTIONAL
if you follow instructions you will be fine.

1) Put WAD Manager 1.3 on your sd card

2) Install the CIOSCORP WADs

can be found in Softmii or MiiWii packages

3) Install CIOS60BF.wad

google "CIOS60HK.zip" or get "cios60.wad" from the offline guide

4) Your system menu will now say "System Files Corrupt" but dont worry! just hold reset and launch the Homebrew Channel and install Preloader 0.29 AGAIN

5) Enable update blocker in preloader. Hold RESET and power on. Change preloader options and hacks

Frequently Asked Questions

How do I fix Homebrew Channel going to a black screen?

reinstall it with bannerbomb

What if I cant install Bootmii? What if the NAND backup fails?

Chances are you will be fine, its just another security measure which I have never needed to use.

Is my console BRICKED!?

If you have Bootmii boot2 or preloader then you are fine. Turn your Wii OFF to the RED light and then hold RESET and turn it on then load the HBC
If you have cIOS installed run cIOS Downgrader
If you dont have cIOS installed use the Offline Downgrade method

Will this work with Softmii? MiiWii? old version of cIOS? etc

Theres no need to uninstall anything first. You can install CIOSCORP on 4.0 using this guide

Will this work with Starfall? Preloader 0.28?

No. You MUST use Preloader 0.29. Starfall hacks wont work on 4.0. Use the latest preloader hacks.ini

Do original discs work with/without CIOSCORP?

Yes. CIOSCORP and CIOS60 only affect Backup Discs

How do I fix the error when installing preloader "current IOS(36) has the fakesign bug fixed"?

Install "IOS36-64-v1042.wad" which can be found on a disc or using the Offline Pack

How do I fix (X)?

Chances are you messed up directions somewhere. Start from Step 1!

Credits: Team Twiizers, Waninkoko, tona, WB3000, Crediar, WiiGator, WiiBlaster, wiiNinja, ubercow