Dedicated to my good friend and mentor, Julien.

Super Mario Land 2: 6 Golden Coins — Recompiled

Release v0.2.0 requires original boot firmware: the 256-byte DMG BIOS for faithful mode and the 2304-byte CGB BIOS for DX. Select it under Settings > System before Play. No ROM or BIOS is distributed. Previous savestates are incompatible; battery saves remain compatible.

The Android ARM64 APK imports the supported V1.0 ROM and firmware once, then prefills the shared launcher. Its Mods page selects DX and widescreen. The Touch controls toggle reveals the pad and Rewind; gamepads also work. Android device gameplay validation was waived for this release. Source builds use the shared host instructions.

Static recompilation of the Game Boy title Super Mario Land 2 - 6 Golden Coins (UE) (V1.0) (CRC32 D5EC24E4) to native code via gbrecompiled, with the shared recomp-ui launcher.

One executable, two recompiled bodies of that one cart: the faithful V1.0 build, and Super Mario Land 2 DX v1.8.1 derived from the same ROM in memory at boot. The launcher's Mods page picks between them — see DX.md.

• super_mario_land_2.toml — faithful body (primary project)
• super_mario_land_2_dx.toml — DX body (V1.0 + recomp/patches/sml2dx_v181.bps)
• extras.c — game hooks (launcher name/platform, ROM CRC gate, mods)
• recomp/launcher/boxart.tga — launcher box art
• ADAPTIVE.md — opt-in adaptive widescreen mod (see Mods in the launcher)

The ROM is not included; supply your own at roms/Super Mario Land 2 - 6 Golden Coins (UE) (V1.0) [!].gb. That is the only ROM this build accepts, for either body — the DX image is derived from it and is never asked for.

The default native BIOS build needs private dmg_boot.bin (256 bytes) and cgb_boot.bin (2304 bytes) under gb-recompiled/boot_roms/, or a CMake GBRECOMP_BIOS_DIR path. Select the DMG BIOS for the faithful game and the CGB BIOS for DX in Settings → System. The launcher remembers both paths and rechecks the requirement when the DX option changes. Firmware is not included.

Hold R to rewind. File states and rb-engine rewind now restore the adaptive camera, actor/spawn tracking and frozen transition image with guest state. Version-1 states are incompatible. Both bodies passed 6,500-frame strict routes at 16:9 and 32:9, including pause/resume and save/rewind checks with zero interpreter execution; this is route coverage, not a complete playthrough.

Screenshots

Faithful (Game Boy)	DX color mod (Game Boy Color)

Adaptive widescreen, faithful body at 32:9:

Adaptive widescreen with the DX color mod, 32:9 and 21:9:

Every frame above is the game's own output composited by the recomp: the centre 160 pixels are the hardware PPU, the margins are rebuilt from the same level data the game is running.

Build (Windows, MSYS2 MinGW64 first on PATH)

git submodule update --init --recursive gb-recompiled recomp-ui
$T='C:\msys64\mingw64\bin'
cmake -G Ninja -S gb-recompiled -B gb-recompiled/build -DCMAKE_C_COMPILER=$T/gcc.exe -DCMAKE_CXX_COMPILER=$T/g++.exe -DCMAKE_MAKE_PROGRAM=$T/ninja.exe -DGBRECOMP_RECOMP_UI=ON -DRECOMP_UI_ENABLE_MODS=ON -DRECOMP_UI_ROOT=$PWD/recomp-ui
ninja -C gb-recompiled/build gbrecomp
gb-recompiled/build/bin/gbrecomp.exe --config super_mario_land_2.toml
gb-recompiled/build/bin/gbrecomp.exe --config super_mario_land_2_dx.toml
cmake -G Ninja -S generated -B generated/build -DCMAKE_C_COMPILER=$T/gcc.exe -DCMAKE_CXX_COMPILER=$T/g++.exe -DCMAKE_MAKE_PROGRAM=$T/ninja.exe -DGBRECOMP_RECOMP_UI=ON -DRECOMP_UI_ENABLE_MODS=ON -DGBRECOMP_LAUNCHER_CONSOLE=gb -DRECOMP_UI_ROOT=$PWD/recomp-ui
ninja -C generated/build
generated/build/Super_Mario_Land_2.exe

Mods (opt-in, default off)

• Adaptive widescreen — Fit to window, 16:9, 21:9, 32:9. See ADAPTIVE.md.
• DX color — Super Mario Land 2 DX v1.8.1 by toruzz. Off, the game runs faithfully; on, the DX patch is applied to your ROM in memory at boot and the Game Boy Color build runs instead. Separate save file. Works together with Adaptive widescreen: the wide margins get the DX background attributes too. See DX.md.

Or from PowerShell: .\Launch.ps1 -Build, then .\Launch.ps1 -DX / .\Launch.ps1 -Faithful to seed the toggle.

Driving a build over TCP (probes)

The engine's debug server (localhost:4370, JSON-per-line) can load a save state, step frames, press buttons and screenshot the presented frame. Its full command list is gb-recompiled/docs/DEBUG_SERVER.md; tools/tcp.py is the client every probe here imports:

python tools\probe_pause_pipe_capture.py          # loads a fixture state, captures 32:9 PNGs

sml2_save, sml2_load and sml2_capture are superseded by the generic save_state, load_state and screenshot commands; they survive only as thin aliases that pin their historic default paths (logs/probe.state, logs/probe.ppm) so older scripts keep working. New code should call the generic commands and pass its own path.

Running / packaging

For a release build, use make_release.ps1 (Windows zip), build-linux.sh (AppImage) or build-macos.sh (.app/.dmg) — they build, stage, gate on the ROM CRC and verify the result. See RELEASE.md.

The build stages the mingw-w64 runtime DLLs (SDL2.dll, libEGL.dll, libGLESv2.dll, zlib1.dll, libgcc_s_seh-1.dll, libstdc++-6.dll, libwinpthread-1.dll) and the launcher assets/ next to generated/build/Super_Mario_Land_2.exe, so it runs from a bare double-click. Without them a PATH that lists another toolchain first (devkitPro) fails with entry point not found. Ship the exe with those DLLs, assets/ and sml2dx_v181.bps.