mGBA Splitscreen - RetroBIOS

Type	libretro
Classification	Community forks
Source	https://github.com/Spuds0588/mgba-splitscreen
Upstream	https://github.com/mgba-emu/mgba
Version	0.1.0
Profiled	2026-10-04
Cores	mgba_splitscreen
Systems	nintendo-gba

Technical notes

mGBA Splitscreen is a fork of mGBA that runs 2-4 linked GBA cores in a single libretro instance over mGBA's lockstep SIO driver. Built from the upstream mGBA tree with -DBUILD_LIBRETRO_SPLITSCREEN=ON (CMakeLists.txt:1036-1058), the fork adds the mgba-splitscreen link fixes (Four Swords handshake assist and a gated deadlock kick) on top of mGBA's library layer. The player instances live in src/platform/libretro-splitscreen/instances.c and reject anything that is not a GBA ROM (instances.c:114-119).

The splitscreen wrapper never performs its own BIOS lookup. Each per-player mCore reaches mGBA's shared GBA core, which looks for gba_bios.bin in the system directory and uses the built-in HLE BIOS (src/gba/hle-bios.c) when it is missing. The core-info declares one optional firmware entry (gba_bios.bin) and only accepts the .gba extension, so GB/GBC/SGB BIOS files that upstream mGBA supports are unreachable here.

1 files | 0 required, 1 optional | 1 in repo, 0 missing | 1 with HLE fallback

gba_bios.bin optional in repo HLE fallback

• System: nintendo-gba
• Size: 16.0 KB
• Validation: size
• Source: src/platform/libretro-splitscreen/mgba_splitscreen_libretro.info:34-37, src/gba/gba.c:520-551
• Platforms: batocera, bizhawk, lakka, misterfpga, recalbox, retroarch, retrobat, retrodeck, retropie, rocknix, romm
• GBA BIOS, same file upstream mGBA uses. HLE replacement built in.

Generated on 2026-10-10T11:26:01Z