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. 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. Fun DraStic is an alternate front end for the same emulator, selectable per game - see Nintendo DS below.
• 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, Atomiswave, and Naomi games from Roms/DC/, Roms/ATOMISWAVE/, and Roms/NAOMI/. It is the default for all three systems; the RetroArch Flycast core remains an alternate, followed by KM Flycast Xtreme when that optional core is installed. 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, save states, and settings use the same durable Flycast locations for all three systems and survive Leaf updates - see Flycast controls.
• Standalone YabaSanshiro is an optional, faster Saturn route for directly launched .ccd, .chd, .cue, .iso, and .mds games. RetroArch YabaSanshiro remains the default because its playlists, compressed-game handling, menu, and disc controls are more complete. The standalone emulator uses its own native menu and save-state format; see Saturn controls.
• Neko Project II kai runs NEC PC-98 software from Roms/PC98/ through RetroArch. It supports disk control for multi-disk software and uses firmware from BIOS/np2kai/ when supplied.
• PUAE 2021 runs Amiga OCS/ECS, AGA, CDTV, and CD32 content from Roms/AMIGA/ through RetroArch. PUAE is available as an alternate through Core. Both support disk control and use model-specific Kickstart firmware from BIOS/puae/.

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

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

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.

Saturn: RetroArch vs standalone

Leaf keeps YabaSanshiro in RetroArch as the Saturn default. It provides the normal Leaf and RetroArch menus and is the route used for .m3u playlists and .zip files.

YabaSanshiro Standalone is an optional faster route for direct .ccd, .chd, .cue, .iso, and .mds launches. Pick it with Core for a compatible game. It is not offered for .m3u or .zip entries because those formats fail in the standalone frontend.

The two routes use different save-state formats, which are not compatible. Standalone uses Saves/YabaSanshiro/ and States/YabaSanshiro/; switch back to the emulator that created a state rather than moving states between them.

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.

Nintendo DS

Leaf lists Nintendo DS as one system, with one ROM folder: Roms/NDS/. Two front ends are available through the Core option:

• DraStic is the default, using Steward Fu’s front end. It’s what the Nintendo DS controls describe.
• Fun DraStic is by tenlevels: a redesigned menu, screen overlays, extra screen layouts, and themes.

Both run the same closed-source DraStic emulator binary. Choose the front end whose menus, layouts, and controls you prefer; the alternate interface does not provide a newer emulator core.

To move a game across, press X on it, choose Core, and pick the other one. To put it back on the default, choose Core again and pick DraStic, or use Reset Override to clear the per-game choice entirely.

Your in-game saves are shared, so a game keeps its progress whichever front end you play it in. Save states and settings are not shared: each front end keeps its own, and a save state you made in one won’t be there in the other. Save in-game before you switch.

Neither one needs a BIOS file of your own; both include DraStic’s own free replacement BIOS, and most games run on it with no setup at all.

If you need original Nintendo files, for example for encrypted ROMs, supply your own dumps using these names and sizes:

File	Size
nds_bios_arm7.bin	16 KB (16,384 bytes)
nds_bios_arm9.bin	4 KB (4,096 bytes)
nds_firmware.bin	256 KB (262,144 bytes)

The two front ends read them from different places on your primary card:

• Fun DraStic reads them directly from BIOS/.
• DraStic reads them from .umrk/mlp1/drastic/system/, which is its durable runtime data folder.

Putting them in BIOS/NDS/ does not make them available to both front ends. Neither location above is replaced by a Leaf update. Your DS username, birthday, favourite colour, and language are emulator settings; supplying nds_firmware.bin does not import those settings from your console.

Both DraStic front ends accept .nds files, and .zip and .7z archives containing one.

DSperate (optional pak)

DSperate, by beebono, is an independent Nintendo DS emulator. Install the DSperate content pak through Pak Rat on Leaf 0.12.0 or newer. On MLP1, it adds another core for the same Nintendo DS system. Choose DSperate in the system’s or game’s Core setting. It keeps your saves separate from both DraStic front ends.

DSperate reads .nds and .zip files. Launching a .7z shows a warning: extract it to .nds, or choose another Nintendo DS emulator.

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/
  puae/
    kick34005.A500
    kick40068.A1200
    kick34005.CDTV
    kick40060.CD32
    kick40060.CD32.ext
  SATURN/
    sega_101.bin
    mpr-17933.bin
  dc/
    dc_boot.bin
    awbios.zip
    naomi.zip
    naomi2.zip
  np2kai/
    font.bmp
  neogeo.zip
  ...

Systems that need a BIOS

• Neo Geo - requires neogeo.zip in BIOS/. Without it, Neo Geo games appear but won’t launch. The file must be named exactly neogeo.zip - files like aes.zip are not used, so don’t drop them into your ROM folders (they would show up as a broken “game”).

• 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 - put Sega Saturn BIOS files in BIOS/SATURN/. The RetroArch YabaSanshiro core uses this folder automatically. Provide a 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. YabaSanshiro Standalone is different: it starts without a BIOS by default, and you pick one per game or per system - see Saturn: choosing a BIOS.

• PlayStation - games generally run without one, but a real BIOS in BIOS/ (for example scph5501.bin for US titles) improves compatibility.

• NEC PC-98 - put np2kai firmware in BIOS/np2kai/. Provide either font.bmp or FONT.ROM for text rendering. Optional firmware dumps such as bios.rom, itf.rom, and sound.rom go in the same folder and can improve compatibility. Optional YM2608 rhythm samples (2608_BD.WAV, 2608_SD.WAV, 2608_TOP.WAV, 2608_HH.WAV, 2608_TOM.WAV, and 2608_RIM.WAV) belong there too. Preserve the filenames expected by np2kai.

• Amiga (PUAE) - put every Kickstart ROM and related file in BIOS/puae/. Both packaged cores use this subfolder rather than root-level BIOS/ or BIOS/AMIGA/. Use the lowercase spelling on a case-sensitive filesystem. PUAE has a limited built-in AROS fallback, but model-specific firmware gives much better compatibility. Common official filenames and accepted Amiga Forever alternatives are:

  Hardware	PUAE filename	Amiga Forever filename	Raw size
  A1000 Kickstart 1.1 NTSC	kick31034.A1000	amiga-os-110-ntsc.rom	256 KB
  A1000 Kickstart 1.1 PAL	kick32034.A1000	amiga-os-110-pal.rom	256 KB
  A500 Kickstart 1.2	kick33180.A500	amiga-os-120.rom	256 KB
  A500 Kickstart 1.3	kick34005.A500	amiga-os-130.rom	256 KB
  A600 Kickstart 2.05	kick37350.A600	amiga-os-205-a600.rom	512 KB
  A600 Kickstart 3.1	kick40063.A600	amiga-os-310-a600.rom	512 KB
  A1200 Kickstart 3.0	kick39106.A1200	amiga-os-300-a1200.rom	512 KB
  A1200 Kickstart 3.1	kick40068.A1200	amiga-os-310-a1200.rom	512 KB
  A4000 Kickstart 3.0	kick39106.A4000	amiga-os-300-a4000.rom	512 KB
  A4000 Kickstart 3.1	kick40068.A4000	amiga-os-310-a4000.rom	512 KB
  CDTV extended ROM	kick34005.CDTV	amiga-os-130-cdtv-ext.rom	256 KB
  CD32 Kickstart	kick40060.CD32	amiga-os-310-cd32.rom	512 KB
  CD32 extended ROM	kick40060.CD32.ext	amiga-os-310-cd32-ext.rom	512 KB
  CD32 combined Kickstart + extended ROM	kick40060.CD32	N/A	1 MB

  These sizes describe raw ROM images; an encrypted Amiga Forever file may include a header. Check the upstream hashes as well as the size.

  A500/OCS games normally use Kickstart 1.3, while A1200/AGA content normally uses Kickstart 3.1. CDTV needs its extended ROM plus an applicable base Kickstart. CD32 needs both CD32 files, unless you have the accepted combined ROM image. If your legally obtained Amiga Forever ROMs are encrypted, place their rom.key in BIOS/puae/ too. PUAE may create user-owned WHDLoad files in this folder; Leaf updates leave them in place. The complete upstream BIOS table, including hashes, is in the official PUAE documentation.

• Dreamcast - BIOS/dc/dc_boot.bin is optional but recommended for the real Dreamcast boot firmware. Current Flycast creates and maintains its own writable NVRAM, so dc_flash.bin is not required.

• Atomiswave and Naomi - put Flycast’s arcade BIOS archives in BIOS/dc/. Atomiswave uses awbios.zip. Base Naomi and Naomi GD-ROM use naomi.zip; Naomi 2 uses the separate naomi2.zip. A few games also need the corresponding game-specific archive, such as airlbios.zip, f355bios.zip, f355dlx.zip, or hod2bios.zip.

BIOS/dc/ is the canonical folder for Dreamcast, Atomiswave, base Naomi, Naomi GD-ROM, and Naomi 2. Central Scrutinizer’s BIOS upload view targets this same shared folder. Standalone and RetroArch Flycast both use BIOS/dc/.

All firmware and arcade BIOS archives are user-supplied. Leaf does not bundle, download, or redistribute them.

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

Saturn: choosing a BIOS

YabaSanshiro Standalone can start a Saturn game two ways: with HLE, a built-in stand-in for the console firmware, or with a real Saturn BIOS file you supply. Neither is right for every game. Some titles only start with a real BIOS; others only start under HLE. So the choice is yours, per game and per system, rather than a global switch.

This applies only to YabaSanshiro Standalone. Select it with Core first (press X on a Saturn game or on the Saturn system); the Saturn BIOS row appears right below Core once it is in force. The RetroArch YabaSanshiro core also uses BIOS/SATURN/, but it has no BIOS row because it selects its expected firmware filename itself.

Saturn BIOS offers:

• Default - on a game, inherit whatever the Saturn system is set to. On the system, go back to HLE.
• HLE - no BIOS file. Use this to opt one game out of a BIOS you selected for the whole system.
• Any BIOS file you have staged - browse to it and press A.

Browsing starts at each installed SD card’s BIOS/SATURN/ folder. You do not need a particular filename or extension for the standalone emulator: a regional or renamed dump is fine, and subfolders below SATURN/ are yours to organize. Nothing is moved, renamed, or copied - Leaf only remembers which file you chose.

Only files of exactly 512 KiB are offered, because that is the size of a Saturn BIOS image. That is a shape check, not a verification: a 512 KiB file could belong to another console entirely, and even a genuine Saturn BIOS is not guaranteed to work with every game. If a game misbehaves, try the other setting.

A game’s own choice wins over the system’s. Reset Overrides clears the BIOS choice along with the core, name, and performance settings, at whichever level you opened the menu.

Two cards, and files that go missing

If you run two SD cards, both cards’ BIOS/SATURN/ folders are offered, and Leaf remembers which card your file came from. Two files with the same name on different cards stay two different choices, and a system-wide selection keeps pointing at the one file you picked no matter which card a given game lives on.

If the file you selected is later renamed, deleted, or is on a card that isn’t in the device, Leaf will not quietly fall back to HLE or to some other file. The Saturn BIOS row says the selection is unavailable, and starting the game is refused with an explanation, so you can put the file back or choose another one. Nothing changes behind your back.

Switching Core to the RetroArch YabaSanshiro core keeps your standalone BIOS choice on file: the row disappears and the choice is ignored for those launches, including when the file is missing, and it comes back when you switch to the standalone again.

Arcade & Neo Geo: extra rules

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

1. Pick the right folder. Leaf organizes arcade games by folder:
   • Roms/ARCADE/ - the normal FinalBurn Neo arcade library.
   • Roms/NEOGEO/ - all Neo Geo sets, arcade ones included. FinalBurn Neo treats Neo Geo as arcade, but Leaf gives Neo Geo its own system (see below).
   • Roms/MAME/ - only if you intentionally maintain a MAME 03+ set.
2. 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.
3. Keep them zipped. Arcade games load from their .zip by exact filename; do not unzip or rename them (the opposite of some other systems).
4. 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.

AES vs MVS: one Neo Geo folder

Leaf has no separate folders for the Neo Geo home console (AES) and arcade cabinet (MVS) - they are one system. Put all Neo Geo games, home or arcade, in Roms/NEOGEO/, zipped, with their original set names. Both are emulated by FinalBurn Neo with the same neogeo.zip BIOS.

If you specifically want the home-console (AES) experience, that’s a runtime setting rather than a folder: while a Neo Geo game is running, open the RetroArch in-game menu, go to Core Options, and set Neo-Geo mode to AES. A BIOS containing the Universe BIOS also lets you pick console/region at boot.

Note that .neo files (the NeoSD / Darksoft flashcart format) are not supported: FinalBurn Neo needs the original zipped ROM sets instead.

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.