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Leaf Leaf

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)

Section titled “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. It comes in two flavors, PPSSPP (Vulkan) as the default and PPSSPP (GLES) as a fallback, switchable with Core. 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 - see PSP controls for the details.
  • 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. DraStic uses MENU as a modifier for save states, layouts, and the transparent second screen - see Nintendo DS controls for the full list.
  • Standalone N64 runs Nintendo 64 games from Roms/N64/ through Leaf’s packaged Mupen64Plus build. The standard RetroArch N64 core is still available as an alternate core, but standalone is the default because it gives Leaf more direct control over the video plugins, performance settings, save-and-quit handoff, and MLP1 display quirks.
  • Standalone Flycast runs Dreamcast games from Roms/DC/. The RetroArch Flycast core is still available as an alternate core, but standalone is the default because it performs noticeably better on this hardware. Like the other standalone emulators it runs its own session: the Menu button opens Flycast’s native menu, correctly oriented for the portrait-mounted screen, and the RetroArch in-game menu doesn’t apply. VMU data and your Flycast settings are kept across Leaf updates - see Dreamcast controls.

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.

When a system has more than one emulator, you don’t need a second ROM folder for it. Keep all of that console’s games in its one folder and switch emulators with the Core option (press X on a game or system; see Adding games). For example, Game Boy Advance games all live in Roms/GBA/ whichever core you pick.

Game Boy Advance: mGBA vs gpSP

Section titled “Game Boy Advance: mGBA vs gpSP”

Leaf keeps mGBA as the default because it has the broader compatibility and accuracy. gpSP is available as a faster alternate: on the MLP1 it delivered about 1.86 times mGBA’s fast-forward rate in a matched reference test scene. Normal-speed play, zipped games, in-game saves, and save states all work through the gpSP path.

To try gpSP for one game, press X on that game, choose Core, then choose gpSP. To return to mGBA, choose mGBA, or use Reset Overrides to clear the game’s custom core and return to the system default.

The two cores keep their saves and save states separate. A save made in one core does not appear in the other, and their save-state formats are not compatible. Do not copy or move save states between mGBA and gpSP; switch back to the core that created the state instead.

Use mGBA when a title fails under gpSP. For example, the homebrew game Glory Hunters exits under the current gpSP build but works in mGBA. A commercial game with an in-game clock works with gpSP’s default automatic RTC setting, but a strict RTC test ROM fails there and passes in mGBA, so mGBA is also the safer choice for RTC homebrew, test software, and ROM hacks. No manual gpSP RTC setting is normally needed.

Nintendo 64: standard vs standalone

Section titled “Nintendo 64: standard vs standalone”

Leaf lists Nintendo 64 as one system, with one ROM folder: Roms/N64/. The difference is the emulator selected by the Core option:

  • Mupen64Plus Standalone is Leaf’s default. It is a native Mupen64Plus package with Rice and GLideN64 video plugins, plus a Leaf-themed overlay for save states, per-game settings, and save-and-quit resume.
  • Mupen64Plus Next is the standard RetroArch/libretro N64 core. Choose it if a specific game behaves better there, or if you specifically need RetroArch’s own in-game menu, shaders, or RetroAchievements path for that title.

We default to standalone because N64 is one of the hardest systems for the MLP1: the native package gives us tighter control over rendering, display rotation, and game-specific settings than the generic RetroArch core path. That makes it the better baseline for the device, while keeping the RetroArch core available as a compatibility fallback.

BIOS (you supply these)

Section titled “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

Section titled “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

Section titled “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.
  • Saturn - requires the Sega Saturn BIOS in BIOS/; the YabaSanshiro core will not boot without it. Provide the standard Saturn BIOS, for example sega_101.bin (Japanese) or mpr-17933.bin (US / European). Without one, Saturn games appear in the launcher but won’t launch.
  • 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

Section titled “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 Roms/ARCADE/ for the normal FBNeo arcade library, or Roms/MAME/ if you intentionally maintain a MAME 03+ set.
  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.

Once they load, Leaf shows arcade games under their real titles rather than the cryptic ROM-set names - see Arcade names for how that works and how to override it.

A note on the hardware

Section titled “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.