# XU4: a reconstruction of Ultima IV

> XU4 recreates Ultima IV for modern systems while loading the original DOS game's data at runtime. Its implementation supports original EGA and upgraded VGA graphics, and its documentation maps file structures such as SHAPES.EGA.

- Type: Case study
- Targets: Game
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-06
- Added to the catalog: 2026-11-09
- Original resource: <https://github.com/xu4-engine/u4>
- Primary source: <https://github.com/xu4-engine/u4/blob/6a7ee3d0079cfdc1c8fb9ba7a3c710a957155a71/README.md>
- Catalog page: <https://awesomerea.org/resources/xu4-ultima-iv-case/>
- Record JSON: <https://awesomerea.org/resources/xu4-ultima-iv-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/xu4-ultima-iv-case/index.md)

## Requirements & limits

- **Prerequisites:** A copy of Ultima IV for DOS is required for runtime data.
- **Scope:** Linux is the primary development platform; Windows builds are also described.
- **License:** GPL-3.0 license.

## Primary sources

1. <https://github.com/xu4-engine/u4/blob/6a7ee3d0079cfdc1c8fb9ba7a3c710a957155a71/README.md>
2. <https://github.com/xu4-engine/u4/blob/6a7ee3d0079cfdc1c8fb9ba7a3c710a957155a71/doc/FileFormats.md>

## More in Games

- [YodaStoriesNG: rebuilding Yoda Stories and Indiana Jones from their data files](https://awesomerea.org/resources/yodastoriesng-case/index.md) · Case study
- [z2rs: an incremental Rust reconstruction of Zelda II checked against an emulator](https://awesomerea.org/resources/z2rs-zelda2-reconstruction-case/index.md) · Case study
- [Zelda3: a C reimplementation of A Link to the Past](https://awesomerea.org/resources/zelda3-case/index.md) · Case study
- [Zeliard: DOS engine analysis and an SDL2 source port](https://awesomerea.org/resources/zeliard-dos-reconstruction-case/index.md) · Case study
- [ZGloom: reimplementing the Amiga game Gloom](https://awesomerea.org/resources/zgloom/index.md) · Case study
- [ZT1-Engine: reconstructing Zoo Tycoon 1 from zoo.exe](https://awesomerea.org/resources/zt1-engine-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.