BIOS & cores

Two things make a game run: a core (the emulator) and, for some systems, a BIOS (the console’s original startup firmware). Leaf handles cores for you; BIOS files you must supply yourself.

Cores (the emulators)

A core is the emulator for a given system. Every supported system’s emulator ships in the release, so games are ready to play as soon as your ROMs are in place; a system shows up in the launcher once its emulator is present on the device. Each emulator is the work of its own authors: the full license text and a pointer to the source for every one ships inside the install under licenses/.

Under the hood:

• RetroArch cores handle the bulk of systems. Leaf’s cores are built with a core builder forked from spruceOS’s build lane, which is itself downstream of libretro-super (the same source the wider libretro ecosystem uses), so they track upstream rather than being hand-maintained forks.
• Standalone PPSSPP runs PSP games; a dedicated build outperforms the RetroArch core on this hardware. PSP ROMs can be .chd, .iso, .cso, or .pbp, and PSP needs no BIOS. Standalone sessions work a little differently: the Menu button opens PPSSPP’s pause menu, and the RetroArch in-game menu and save states don’t apply. Volume keys work as usual.
• Standalone DraStic runs Nintendo DS games (.nds) from Roms/NDS/, and needs no BIOS of your own. Like PPSSPP it’s a standalone session: the Menu button opens DraStic’s own menu (save states, options, and the second-screen layout live there), so the RetroArch in-game menu doesn’t apply. Volume keys work as usual.
• Dreamcast and Nintendo 64 run through their RetroArch cores today (Flycast and Mupen64Plus-Next); dedicated standalone builds are planned.

Because Leaf runs upstream RetroArch, features that upstream adds (including RetroAchievements with compatible cores) come along for the ride rather than needing to be reimplemented.

Note

The heaviest systems (PSP, Dreamcast, N64) are demanding on this hardware. Whether a given game runs at full speed varies by title; treat these as “best effort,” not guaranteed.

BIOS (you supply these)

A BIOS is the copyrighted firmware from the original console. Leaf never includes BIOS files, and it can’t legally distribute them. This is standard across all emulation projects: you provide your own, ideally dumped from hardware you own.

Where BIOS files go

Put them in the BIOS/ folder at the root of the SD card:

BIOS/
  neogeo.zip
  ...

Systems that need a BIOS

• Neo Geo - requires neogeo.zip in BIOS/. Without it, Neo Geo games appear but won’t launch.
• Arcade (FinalBurn Neo / FBNeo) - many arcade games depend on a BIOS or a parent ROM set (for example, CPS systems need their BIOS). These also live in BIOS/ or alongside the game set.
• PlayStation - games generally run without one, but a real BIOS in BIOS/ (for example scph5501.bin for US titles) improves compatibility.

Handheld systems like Neo Geo Pocket / Color need no BIOS; plain ROMs just work.

Arcade & Neo Geo: extra rules

Arcade emulation is the fussiest part of any handheld. Three things matter:

1. Match the ROM-set version. Arcade cores only load ROM sets that match the core’s expected version. A set from the wrong version silently fails to load even when the game name looks right. Use a set that matches the core.
2. Keep them zipped. Arcade games load from their .zip by exact filename; do not unzip or rename them (the opposite of some other systems).
3. Parents & BIOS. Clones reference their parent set (both must be present), and neogeo.zip acts as the shared BIOS for the whole Neo Geo library.

A note on the hardware

The Miniloong Pocket 1’s CPU comfortably handles 8- and 16-bit systems and handhelds. Heavier systems (e.g. anything approaching 3D-era consoles) are demanding on this class of hardware; expect mixed results even with the right core and BIOS in place.