# GLaBIOS: a scratch-built 8K ROM BIOS

> A scratch-built open ROM BIOS for vintage PC, XT, and 8088-class machines. The shipped assembly source src/GLABIOS.ASM is the build input; src/MAKE.BAT runs MASM and LINK, then GLA2ROM writes GLABIOS.ROM, which the GLA2ROM readme calls an 8KiB ROM image.

- Type: Case study
- Targets: Firmware
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-03
- Added to the catalog: 2026-11-09
- Original resource: <https://github.com/640-KB/GLaBIOS>
- Primary source: <https://github.com/640-KB/GLaBIOS/blob/b98b0fe396466fa41466a9521f40987c989ae077/README.md>
- Catalog page: <https://awesomerea.org/resources/glabios-rom-bios-case/>
- Record JSON: <https://awesomerea.org/resources/glabios-rom-bios-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/glabios-rom-bios-case/index.md)

## Requirements & limits

- **Prerequisites:** src/GLABIOS.ASM is in the tree. src/MAKE.BAT runs MASM GLABIOS, LINK GLABIOS, and then GLA2ROM on GLABIOS.EXE to write GLABIOS.ROM. src/gla2rom/README.md says that command produces an 8KiB ROM image and must run under DOS or a DOS emulator.
- **Scope:** The README describes an 8K PC-compatible BIOS for vintage PC, XT, and 8088 machines; its pinned commit is v0.4.2 and also describes a Version 0.8b preview.
- **License:** LICENSE is the GNU GPL version 3 text, and the README identifies the project as GPLv3.

## Primary sources

1. <https://github.com/640-KB/GLaBIOS/blob/b98b0fe396466fa41466a9521f40987c989ae077/README.md>
2. <https://github.com/640-KB/GLaBIOS/blob/b98b0fe396466fa41466a9521f40987c989ae077/src/GLABIOS.ASM>
3. <https://github.com/640-KB/GLaBIOS/blob/b98b0fe396466fa41466a9521f40987c989ae077/src/MAKE.BAT>
4. <https://github.com/640-KB/GLaBIOS/blob/b98b0fe396466fa41466a9521f40987c989ae077/src/gla2rom/README.md>
5. <https://github.com/640-KB/GLaBIOS/blob/b98b0fe396466fa41466a9521f40987c989ae077/LICENSE>

## More in Firmware and hardware

- [TC66 custom firmware: a replacement image for the RuiDeng USB-C meter](https://awesomerea.org/resources/tc66-meter-firmware-case/index.md) · Case study
- [UV-K5: an open reimplementation of Quan Sheng firmware v2.1.27](https://awesomerea.org/resources/uv-k5-firmware-case/index.md) · Case study
- [R64Emu: low-level Nintendo 64 hardware reconstruction](https://awesomerea.org/resources/r64emu-n64-case/index.md) · Case study
- [Nuked-MD-FPGA: Sega Mega Drive chipset reconstruction](https://awesomerea.org/resources/nuked-md-fpga-case/index.md) · Case study
- [CamLink 4K: replacement gateware and firmware for an Elgato capture card](https://awesomerea.org/resources/camlink-4k-case/index.md) · Case study
- [pw_firm: a Pokéwalker firmware decompilation](https://awesomerea.org/resources/pw-firm-pokewalker-decomp-case/index.md) · Case study

## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.