Nintendo Game Boy (2 Players)

• Emulator: RetroArch
• Core: libretro: TGBDual
• Folder: /userdata/roms/gb2players
• Accepted ROM formats: .gb, .gb2, .gbc2, .zip, .7z

No Game Boy (2 players) emulator in Batocera needs a BIOS file to run.

ROMs can ordinarily be put into the roms/gb2players/ folder. This will use a single ROM for both players in the linked game instances (Player 1's saves are stored in saves/gb2player). Player 2 will use a temporary blank save file that is removed when the session ends. Great for PVP games that don't rely on user save files such as Tetris or Ikari no Yousai.

This is the only available way to use GB2Player on Batocera v31 and lower.

If instead you'd like to use two different ROMs, read the section on it below.

Alternative title: POKEMON, YEAH! POKEMON TIME CAPSULE! POKEMON TRADING! POKEMON BATTLING! AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA POKEMON!!!

In Batocera v32 and higher, it is possible to use two different ROMs instead.

1. Copy your Game Boy/Game Boy Color ROMs to their respective solo ROM directory, ie. roms/gb and roms/gbc respectively. For example:

   roms/
   ├─ gb/
   │  └─ Pokemon Yellow.zip
   └─ gbc/
      └─ Pokemon Crystal.zip

2. Create a new text file named <game 1 title> and <game 2 title>.gb2 containing the filenames of the games you intend to link play with prepended with gb: or gbc: depending on which folder they're stored in. For example:

   Pokemon Yellow and Pokemon Crystal.gb2

   gb:Pokemon Yellow.zip
   gbc:Pokemon Crystal.zip

   Class A (Dual Mode) Game Boy Color games can be played on the Game Boy (obviously without color); these were typically indicated by having a black cartridge to differentiate them from regular Game Boy games. Class B Game Boy Color games can't be played on the original Game Boy. Such games typically feature the disclaimers like “Only for Game Boy Color”.

   Libretro/TGB Dual doesn't care, and will run either game with its appropriate system. Check first before attempting this, Game Boy Color games will default to using the Game Boy Color mode of the emulator!

   You can check out which games are class A on Wikipedia's list of Game Boy Color games.

3. Save this text file to the roms/gb2player/ directory. For example:

   roms/
   ├─ gb/
   │  └─ Pokemon Yellow.zip
   ├─ gbc/
   │  └─ Pokemon Crystal.zip
   └─ gb2players/
      └─ Pokemon Yellow and Pokemon Crystal.gb2

4. Update your game list and now your game will appear in the GB2Player system!

By default, the save files are grabbed from saves/gb2players/<game name for player 1>.srm and saves/gb2players/<game name for player 2>.srm for the different games respectively. This can be used for a quick and dirty way to say trade Pokemon between generations.

But what if you wanted this to all be automated?

In Batocera v32 and higher, it is possible to use two different ROMs from their single-player Game Boy and/or Game Boy Color systems with their respective single-player save file locations instead. This utilizes Python scripts to automate the copying/overwriting process between saves/gb2players/ and saves/gb and/or saves/gbc.

1. Set up your unique ROMs as detailed above.
2. On the GB2Player game list, press [SELECT] to bring up the system-specific options and navigate to ADVANCED SYSTEM OPTIONS.
3. Scroll down to SYNC SAVE FILES and set this to “ON”.

When launching a game through the GB2Player system, the SRM save files for both the ROMs will be temporarily copied from their respective saves/gb/ and/or saves/gbc/ folder(s) to saves/gb2player/ (overwriting any files currently there). Upon exiting the game, the saves will be copied back from saves/gb2player to their respective saves/gb/ and/or saves/gbc/ folder(s).

Save states are not copied, only SRM native save files.

In case any of that was confusing here's a professional grade flowchart visualizing what happens based on what configuration/source ROMs are used:

RetroArch (formerly SSNES), is a ubiquitous frontend that can run multiple “cores”, which are essentially the emulators themselves. The most common cores use the libretro API, so that's why cores run in RetroArch in Batocera are referred to as “libretro: (core name)”. RetroArch aims to unify the feature set of all libretro cores and offer a universal, familiar interface independent of platform.

RetroArch offers a Quick Menu accessed by pressing [HOTKEY] + which can be used to alter various things like RetroArch and core options, and controller mapping. Most RetroArch related settings can be altered from Batocera's EmulationStation.

Standardized features available to all libretro cores: gb2players.videomode, gb2players.ratio, gb2players.smooth, gb2players.shaders, gb2players.pixel_perfect, gb2players.decoration, gb2players.game_translation

TGB Dual is an open source (GPLv2) GB/GBC emulator with game link cable support.

We use the latest Libretro core. See the official documentation for more information.

Here are the default Game Boy (2 players)'s controls shown on a Batocera Retropad:

For further troubleshooting, refer to the generic support pages.