bk-emulator - RetroBIOS

Type	libretro
Classification	Community forks
Source	https://github.com/libretro/bk-emulator
Upstream	https://github.com/emestee/bk-emulator
Version	1.00
Profiled	2026-03-23
Cores	bk
Systems	elektronika-bk

Platform details

bios_mapping: - source_ref: libretro.c:718-760, boot.c:83-116 - note: ROM directory is {system_dir}/bk/ (libretro.c:724-726).

Model selection via core option "bk_model" determines which ROMs are loaded. The core shuts down immediately if any required ROM for the selected model is not found.

**model_rom_map:**
- source_ref: libretro.c:734-756, boot.c:83-116
- note: BK-0010:            MONIT10.ROM + FOCAL10.ROM

BK-0010.01: MONIT10.ROM + BASIC10.ROM BK-0010.01 + FDD: MONIT10.ROM + DISK_327.ROM BK-0011M + FDD: B11M_BOS.ROM + DISK_327.ROM + BAS11M_0.ROM + BAS11M_1.ROM + B11M_EXT.ROM Slow BK-0011M: same as BK-0011M + FDD Terak 8510/a: TERAK.ROM

**rom_loading:**
- source_ref: libretro.c:1050-1107
- note: load_rom_file() first tries {romdir}/{filename} with original casing.

If not found, retries with the filename converted to lowercase. Returns NULL and shuts down the core on failure.

Technical notes

Files go in {system_dir}/bk/. Each BK model requires a specific set of ROMs. The default model is BK-0010 which needs MONIT10.ROM and FOCAL10.ROM. Changing the core option "bk_model" changes which ROMs are loaded. The core shuts down if a required ROM is missing (no fallback or pseudo-BIOS). If a ROM file with uppercase name is not found, the core retries with the filename lowercased.

9 files | 1 required, 8 optional | 9 in repo, 0 missing

MONIT10.ROM required in repo

• Path: bk/MONIT10.ROM
• Size: 8.0 KB
• Aliases: monit10.rom
• Validation: size
• Source: main.c:53, boot.c:107
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retropie
• BK-0010 monitor ROM (8 KB). Loaded at address 0100000. Required for all BK-0010 models (0, 1, 2).

FOCAL10.ROM optional in repo

• Path: bk/FOCAL10.ROM
• Size: 24.0 KB
• Aliases: focal10.rom
• Validation: size
• Source: libretro.c:15, boot.c:110
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retropie
• FOCAL interpreter ROM (24448-24576 bytes). Loaded at 0120000. Used by BK-0010 (model 0, default).

BASIC10.ROM optional in repo

• Path: bk/BASIC10.ROM
• Size: 24.0 KB
• Aliases: basic10.rom
• Validation: size
• Source: libretro.c:16, boot.c:110
• Platforms: batocera, lakka, retroarch, retrobat, retropie
• BASIC interpreter ROM (24448-24576 bytes). Loaded at 0120000. Used by BK-0010.01 (model 1).

DISK_327.ROM optional in repo

• Path: bk/DISK_327.ROM
• Size: 4.0 KB
• Aliases: disk_327.rom
• Validation: size
• Source: main.c:54, boot.c:99, boot.c:113
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retropie
• Floppy disk controller ROM (4 KB). Loaded at 0160000 for BK-0010.01+FDD (model 2), or into system_rom for BK-0011M (model 3/4).

B11M_BOS.ROM optional in repo

• Path: bk/B11M_BOS.ROM
• Size: 8.0 KB
• Aliases: b11m_bos.rom
• Validation: size
• Source: main.c:55, boot.c:98
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retropie
• BK-0011M system ROM / BOS (8 KB). Loaded into system_rom at offset 0. Required for BK-0011M (model 3/4).

B11M_EXT.ROM optional in repo

• Path: bk/B11M_EXT.ROM
• Size: 8.0 KB
• Aliases: b11m_ext.rom
• Validation: size
• Source: main.c:56, boot.c:102
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retropie
• BK-0011M extended BOS ROM (8 KB). Loaded into rom[1] at offset 8192. Required for BK-0011M (model 3/4).

BAS11M_0.ROM optional in repo

• Path: bk/BAS11M_0.ROM
• Size: 16.0 KB
• Aliases: bas11m_0.rom
• Validation: size
• Source: main.c:57, boot.c:100
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retropie
• BK-0011M BASIC ROM part 0 (16 KB). Loaded into rom[0]. Required for BK-0011M (model 3/4).

BAS11M_1.ROM optional in repo

• Path: bk/BAS11M_1.ROM
• Size: 8.0 KB
• Aliases: bas11m_1.rom
• Validation: size
• Source: main.c:58, boot.c:101
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retropie
• BK-0011M BASIC ROM part 1 (8 KB). Loaded into rom[1] at offset 0. Required for BK-0011M (model 3/4).

TERAK.ROM optional in repo

• Path: bk/TERAK.ROM
• Size: 128 B
• Aliases: terak.rom
• Validation: size
• Source: boot.c:94
• Terak 8510/a boot ROM (128 bytes). Used when model is set to Terak 8510/a (model 9).

Generated on 2026-09-14T09:03:09Z