BlastEm - RetroBIOS

Type	standalone + libretro
Classification	official_port
Source	https://github.com/libretro/blastem
Upstream	https://www.retrodev.com/blastem/
Version	v0.6.3-pre
Profiled	2026-03-23
Cores	blastem
Systems	sega-megadrive, sega-mastersystem

Source analysis

tmss:

- **standalone_support:** True
- **libretro_support:** False
- **default_model:** md1va3
- **default_tmss:** off
- **rom_filename:** tmss.md
- **rom_size:** 2048
- **config_path:** systemtmss_path
- **source_ref:** genesis.c:1910
- **notes:** TMSS ROM is loaded from tmss.md (configurable via system/tmss_path).

Models with tmss=on: md1va6, md2va1, md2va2, md3va1, md3va2. Models with tmss=off: md1va0, md1va3 (default), teradrive. The libretr... sega_cd:

    - **supported:** False
    - **source_ref:** system.c:16
    - **notes:** TODO comment only: 'Differentiate between vanilla Genesis and Sega CD/32X games'
**jaguar_bios:**

    - **libretro_relevant:** False
    - **notes:** blastjag (jaguar.c) is a separate standalone binary, not compiled

into the libretro core. Requires BIOS as first CLI argument.

Technical notes

BlastEm is a cycle-accurate Sega Mega Drive/Genesis emulator with basic Master System support. In standalone mode it supports TMSS ROM loading and multiple hardware models (MD1 VA0 through MD3 VA2, Teradrive). The Jaguar emulator (blastjag) is a separate standalone binary, not part of the libretro core.

The libretro port (libblastem.c) does NOT expose any core options and defaults to model md1va3 which has TMSS disabled. There is no way to select a TMSS-enabled model through the libretro interface.

Even if a TMSS-enabled model were forced, read_bundled_file() in the libretro build only serves rom.db and returns NULL for tmss.md, so TMSS ROM loading would fail (fatal_error at genesis.c:1923).

Sega CD / Mega CD is not supported (only a TODO comment in system.c:16). No BIOS files are required or loaded by the libretro core.

2 files | 0 required, 2 optional | 1 in repo, 1 missing | 1 with HLE fallback

rom.db -optional, HLE available

• System: sega-megadrive
• Source: libblastem.c:532-542 read_bundled_file()
• Platforms: lakka, retroarch, retrodeck, retropie
• ROM feature database (game-specific mapper/save config). Embedded in core, external is optional override.

tmss.md -optional, standalone, missing from repo

• System: sega-megadrive
• Size: 2.0 KB
• Source: genesis.c:1910-1923
• TMSS startup ROM. Standalone only (models md1va6, md2va1+). Libretro core uses md1va3 (tmss off), no way to change.

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