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# PokeMini - RetroBIOS

Type | libretro
Classification | community_fork
Source | https://github.com/libretro/PokeMini
Upstream | https://sourceforge.net/projects/pokemini/
Version | v0.60
Profiled | 2026-03-24
Cores | pokemini
Systems | nintendo-pokemon-mini

Platform details

bios_mapping: - target: $000000-$000FFF in Pokemon Mini address space (4 KB) - source_ref: source/PokeMini.h:38, source/Hardware.c:144-145 - notes: PM_BIOS is a 4096-byte array. CPU reads from address range

$000000-$000FFF are served directly from this buffer. The BIOS handles interrupt vectors, hardware init, and the startup logo.

    **freebios_fallback:**
    - source_ref: freebios/freebios.c, source/PokeMini.c:209-214
    - notes: FreeBIOS is a 4096-byte open-source replacement embedded in the

binary as a C array. It provides basic interrupt vectors and startup code. Loaded by default at PokeMini_Create() and used as fallback when bios.min is not found on disk.

    - freebios_hashes: {'md5': 'd6c3ff5abc88f7c42f1a5edd6889f9cf', 'sha1': 'b40421defb005e836913e4e39dc1a18aa3b8887e', 'size': 4096}
    **load_priority:**
    - source_ref: source/PokeMini.c:515-523
    - notes: During PokeMini_Reset(), the core first reloads FreeBIOS as a

safe baseline, then attempts to load bios.min from disk. If the file exists and is exactly 4096 bytes, it replaces FreeBIOS. The forcefreebios flag (hardcoded 0 in libretro) controls this: when 0, the core always prefers real BIOS over FreeBIOS.

Technical notes

PokeMini is a Pokemon Mini handheld emulator ported to libretro.

The core has an embedded FreeBIOS (open-source replacement) compiled directly into the binary from freebios/freebios.c. This means the real BIOS is never strictly required -- games will run with FreeBIOS alone, though compatibility may differ from the original firmware.

BIOS loading sequence in the libretro port:

1. PokeMini_Create() clears PM_BIOS (4096 bytes at $000000-$000FFF), then loads FreeBIOS into it via memcpy (source/PokeMini.c:116). PokeMini_FreeBIOS is set to 1.

2. retro_load_game() calls PokeMini_Reset(0) after loading the ROM.

3. PokeMini_Reset() checks forcefreebios (hardcoded to 0 in the libretro port, libretro.c:499). Since FreeBIOS is currently loaded and forcefreebios is 0, it enters the real-BIOS path (source/PokeMini.c:518-523):

   - Reloads FreeBIOS as a safety fallback
   - Checks if CommandLine.bios_file exists on disk
   - If found, overwrites PM_BIOS with the real BIOS via PokeMini_LoadBIOSFile(), sets PokeMini_FreeBIOS to 0

4. If bios.min is missing, FreeBIOS stays loaded and emulation proceeds normally.

File path construction (libretro.c:565): sprintf(CommandLine.bios_file, "%s%cbios.min", g_system_dir, slash) The core looks for bios.min directly in the system directory root, no subdirectory.

There is no core option to toggle FreeBIOS in the libretro port. The standalone PokeMini has a forcefreebios setting, but the libretro wrapper hardcodes it to 0 (always prefer real BIOS when available).

FreeBIOS (freebios/freebios.min) is 4096 bytes, a clean-room reimplementation. It is NOT the official Nintendo Pokemon Mini BIOS.

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

`bios.min` -optional, HLE available : Pokemon Mini official BIOS

- System: nintendo-pokemon-mini
- Size: 4.0 KB
- Source: `source/PokeMini.c:189-206 (PokeMini_LoadBIOSFile), libretro/libretro.c:565 (path)`
- Platforms: lakka, recalbox, retroarch, retrobat, retrodeck, retropie
- Mapped at $000000-$000FFF (4 KB). Read via Hardware.c:144-145. Falls back to embedded FreeBIOS if missing.

Generated on 2026-03-25T14:56:43Z