This tutorial will teach you how to properly edit a Nintendo GameCube ISO's Game ID for your mods.

To start, let's explain what a Game ID actually is.

A Game ID is written on the first few sectors of every Nintendo GameCube ISO by the game developers. Sometimes, changing it can cause issues in Dolphin Emulator (changing the first letter makes it lag.)

Let's explain the structure of a Game ID. We're going to use Luigi's Mansion (USA) to explain this.

GLME01

G - Platform/Console ID (G = GameCube) (is also D for some promotional kiosk discs, unlicensed Action Replay disc and U for GBA bootdisc.)

LM - Game Code (LM = Luigi's Mansion)
E - Region Letter (E = America)

01 - Maker Code (01 = Nintendo)

A modder has a few good reasons to edit a Game ID and not to edit a Game ID. What are they?

• A reason one may not edit the Game ID is to avoid issues, if the edited Game ID already exists in the GameCube database

• One may want to create a new Game ID since it may conflict with existing base-game save data when saving on console. (save data .GCI files contain the Game ID in them too.)

• They may want to publish their mod on the GameTDB custom section and needs a new Game ID to avoid conflicting with the base-game in the database.

When changing Game IDs, it's recommended to keep GLM (if you're modding Luigi's Mansion) or keep the first three bytes intact.

Why?

Well, changing the G could be a problem for Dolphin Emulator. Dolphin scans the Game ID of every game to apply certain patches to it. AKA, if you changed G to L on your mod, it would detect the game as a Wii Virtual Console game and run patches not meant for GameCube; therefore causing lag. If you changed it to R, (Revolution/Wii), it would do the same. 

So if you are modding GameCube, it's recommended to keep the first three bytes intact.

For example, Luigi's Final Ghosthunt uses GLMLFG as it's Game ID. Changing the E or 01 does not matter, as Dolphin doesn't even read those. Region is listed another way, I made a tutorial explaining on how to change that. 01 is just irrelevant entirely as it's not read by anything. 01 is just there to let the developers know who the publisher is. 01 is Nintendo, and here's a list of all of them, anything other than these should work.

01 - Nintendo

08 - Capcom

41 - Ubisoft

4F - Eidos

51 - Acclaim

52 - Activision

5D - Midway

5G - Hudson

64 - Lucas Arts

69 - Electronic Arts

6S - TDK Mediactive

8P - Sega

A4 - Mirage Studios

AF - Namco

B2 - Bandai

DA - Tomy

EM - Konami 

a