Game Genie (Game Boy)

The Game Boy Game Genie cartridge.

The Game Genie is a runtime ROM modification device for the original Game Boy. Much like the the NES Game Genie, it allows up to three bytes to be altered at a time. The format is XXX-YYY-ZZZ, with ZZZ being a compare address to determine which will isolate the new code to the specific ROM bank.

A small handbook for codes was included in the back of the unit enclosed by a small door. The books were updated and revised with more codes on a semi-frequent basis by Codemasters. A regular sized paperback was also included with the unit as well to provide the user with information on basic operation, maintenance, and how program their own codes.

There are two buttons located on the front of the unit. The white button labeled "CODE SCREEN" will jump reset the Game Boy BIOS (GBA, SP, etc). This will reload the code list in RAM and take you to the code screen where you can write down the codes and make alterations and begin the game.

The green button labeled as "CODES ON/OFF" will activate or deactivate all further ROM byte executions from the Game Genie, as indicated by the green LED light on the unit turning on or off.

Non-Monochrome Game Compatibility

There is a way to trick the game genie into working with non-monochrome games with GBC hardware, though the game will be in monochrome mode, and it will most likely damage the SRAM and delete all saved data on the cartridge. Tony Hedstrom here discovered a trick that basically will load the game in monochrome by performing a cartridge swap. The game Genie is also compatible with the Game Boy Player and Game Boy Advance, and Game Boy Advance SP though only supporting regular monochrome games.

Compatibility with the Super Game Boy

The Game Genie is compatible with the Super Game Boy but you will need to physically modify the unit so it will fit into the Super Game Boy/2. There was an adapter that was released and sold by Microsystems Development Technologies, Inc. located in San Jose. More info can be found here Genie to Super Game Boy Adapter.

Using the SNES Game Genie to implement codes

Game Boy Game Genie codes can be converted and entered into a SNES Game Genie to achieve in-game effects, as ugetab demonstrated this prowess using Super Mario Land 2 and Castlevania Legends. Using a code provided as example from the former game allows you to play the chance game for free, and a simple code from the latter game allows you to walk right fast. You will need a Game Genie that is modifyed to add the expansion pins otherwise you will get no sound, the game will be slowed down with graphical lines. This happens because the Super Game Boy outputs the Game Boy audio and various file transfer registers (for SGB functions) and SNES timing sync.

A simple tutorial can be found here on how to perform this modification to your SNES Game Genie. This will allow FX chip games to run.

I have yet to determine if the codes will work with a SNES Pro Action Replay MK3, as it allows you convert SNES Game Genie codes to ROM addresses, or at least I don't recall.

Secret Developer Messages

To access these, press the specified buttons in order while the code screen is displayed. Two are unused and are not associated with button access, and can only accessed by hacking the Game Genie ROM, though they can still be accessed using hardware via Codebreaker cheat Device.

Up, Down Left Right
Congratulations! You've found the easy secret! Now find the hard ones!

B, A, Left, Right, Select
Help! I'm a prisoner in a Game Genie factory!

Up, Up, A, B, A, Down, Down
Game Genie built by: Richard Aplin code by: Jon the Programmer managed by: Paul Ranson.

Right, Up, Down, Up, Left, Up, Down, Up
Poems have, rhymes, sometimes.

B, A, B, Right, Left, Down, Up
There's rain outside, and that is why a, laundry day, needs a clothes dryer.

A, A, A, A, B, B, B, Start
Washing, washing on the line, who's the fairest of the fine? Bluey Whiteness!

Right, Left, Right, Left, Down, Down, Up, Up
Provocation is not a job for amateurs.

A, B, A, B, B, A, A, Select
'Breezy':- Fresh air from the Alps! Comes in an easy-to-use aerosol can!

A, Left, Left, A, B, Right, Right, B
(This one isn't actually a message. Everything below the words "Code Screen," but above the copyright notice, is flipped upside down. The codes are still in their proper order, but the characters are upside down)

Unused Developer Messages

There are two additional messages that can only be accessed by using a Codebreaker cheat device with the Game Genie plugged in, and the codes entered. As explained earlier, this process is vaguely convoluted but it works once you get the hang of achieving a proper setup. Codes from both Game Genie and Codebreaker unit can be used in conjunction to affected the Game Boy game inserted into the Game Genie giving you room for three additional ROM patch codes.

To access these messages, press Up, Down, Left and Right at the code screen (all Game Genie revisions) and use either the Game Genie codes (oddly enough) for emulators, or the Codebreaker codes if you are planning on seeing the messages on hardware.

Message 1:

• Game Genie:

15B-48F-3BC + CCB-79F-6E6 + 0BB-7AF-D5A

• Codebreaker:

000B48-15 + 000B79-CC + 000B7A-0B

Message 2:

• Game Genie

13B-4BF-912

• Codebreaker

000B4B-13

It is assumed that the first message was not given access via direct button combinations because it might freak out the user into thinking their Game Boy would explode. It is unknown why the second message was not made accessible.

• 

  Unused Developer Message 1 Part 1

• 

  Unused Developer Message 1 Part 2

• 

  Unused Developer Message 2

Known Versions

• v1.17
• v2.1 - The current dump is a hack of 1.17 and was likely hacked to load in old emulators.

Credits

• Game Genie built by: Richard Aplin
• Code by: Jon the Programmer
• Managed by: Paul Ranson

Screenshots

1.17

• 

  Screen 1

• 

  Screen 2

• 

  Code screen

2.1

• 

  Screen 1

• 

  Screen 2

• 

  Code screen

Hardware

• 

  Game Genie box

• 

  Game Genie cartridge

• 

  SNES/Game Boy Game Genie flyer

External Links

• Jeff Frohweins webpage at devrs.com.
• Cheatmaster's webpage (Internet Archive)

Game Genie
Galoob
Game Boy - Game Gear - NES - Genesis - Super Nintendo - Sega CD (Cancelled)
Hyperkin
DS/DSi/3DS - PSP (Cancelled) - Wii (Cancelled) - PlayStation 3