wiisixtyfour's blog

Click here to edit subtitle


Devolution - What Is It?

Posted by wiisixtyfour on January 18, 2013 at 4:40 AM

If you've seen my YouTube video about Devolution then you already know that it's a Gamecube ISO loader, but how does it work?


Well first off, most of you know that the Wii has a "Gamecube mode" in which the hardware that is Wii-specific turns off and the Wii basically becomes a Gamecube. In "Gamecube mode" you cannot access the USB ports on the Wii, use Wii remotes, or use the Wii's internet connection. Gamecube games run on MIOS, while Wii games use IOS.

So can we run Gamecube games using IOS?

The answer is, sort of. Since the Wii and Gamecube are so similar in hardware and architecture, it is possible to load gamecube games with IOS, however, that is not all that must be done. Gamecube games like running at Gamecube speed. If you run it in "Wii mode" using IOS it will try to run at Wii speed which is much faster and that causes issues. Along with speed issues, some of the functions that work for Gamecube do not work on Wii, so there may be graphical errors or even games that refuse to run.

There is a video by crediar which demonstrates a Gamecube game at Wii speed.

You need Adobe Flash Player to view this content.

So how do we fix this?

What Devolution does is tell the game to run at Gamecube speed even though it's using IOS in "Wii mode." This also means that there is some of the CPU power as well as memory that isn't being used. Devolution is able to use the extra power and memory space to control the Wii-specific hardware such as USB drive or SD card and it may contain patches that allow the games to run correctly. In the future it should also be possible to use Wii remotes to control the games. But telling the Wii how to run the game does not fix all of the issues when running a Gamecube game in "Wii mode." Devolution applies patches to the games when they are loaded. Some of the patches are game-specific and some are just general Gamecube commands to Wii IOS commands and changing all of the disc read functions so that they load from USB or SD.

So why don't we make an IOS that is already compatible with Gamecube games?

Well theoretically it's possible, but it's also intrusive and there could be problems with different Wii's. Devolution uses the Homebrew Channel to get access to all of the Wii's hardware without the need for IOS patches or custom IOSes. Because of this, it will work on any Wii (with the Homebrew Channel) right out of the box, so to speak.

One more feature of Devolution is the "Anti-Piracy" measures which require you to verify your disc one time before you can play the game. What it does is create a file that is basically a signature, specific to the game, the Wii that it is run on, as well as the device the game is stored on. It makes it impossible to simply copy the verification files and impossible to use copied game ISOs without having the physical disc. It's unknown, at the moment, what measures will be taken for Wii's that cannot read Gamecube games.

In short, Devolution loads Gamecube games from a USB drive or SD card and patches it so it can run on the Wii's IOS in Wii mode. The patches allow the games native functions to work as Wii functions. It uses the Homebrew Channel to access all the Wii's hardware natively so no intrusive Wii system patching is necessary. It cannot be used for piracy because of the disc verification. In the future it should be able to use Wii remotes to control Gamecube games.

That is the general idea (as I understand it) of how Devolution works. I hope you have learned something from this post; the way these things work is something that interests me and I wanted to share my knowledge of the subject for any of you who are interested as well. Please note that some of this may not be technically correct, but it is the basic explanation of the method used. Thanks for reading!

Check out my video about Devolution here: YouTube

Feel free to ask any questions in the comments below.


Categories: Wii, Homebrew