# LEGO Island: source reconstruction with separately reported exact rebuilds

> Reconstructs the English LEGO Island 1.1 source for its original 32-bit Windows target. The project distinguishes function-comparison reports, ReproBit’s reported byte-identical retail rebuilds and ordinary developer builds; its modern portable adaptation is a separate repository.

- Type: Case study
- Targets: Game
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-10-17
- Added to the catalog: 2026-10-17
- Original resource: <https://github.com/isledecomp/isle>
- Primary source: <https://github.com/isledecomp/isle/blob/8119bd013645972c72480e4de21529f1e91ce5c7/README.md>
- Catalog page: <https://awesomerea.org/resources/lego-island-decomp-case/>
- Record JSON: <https://awesomerea.org/resources/lego-island-decomp-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/lego-island-decomp-case/index.md)

## Requirements & limits

- **Prerequisites:** Exact verification requires the user’s matching English 1.1 CONFIG.EXE, ISLE.EXE and LEGO1.DLL, the original Visual C++ 4.2 toolchain, Python 3.11+, Git and ReproBit; Linux/macOS also need Wine.
- **Prerequisites:** Running the rebuilt executables still requires the original installed game data and the documented data paths. The README notes that d3drm.dll may also be needed on newer Windows systems.
- **Testing evidence:** The pinned README reports a cold rebuild matching all three retail binaries byte for byte.
- **Scope:** The ordinary CMake path is for development and is not the release-verification path. This repository targets 32-bit Windows only; cross-platform and Web support belongs to isle-portable.
- **License:** The repository carries the LGPLv3 license; original game data and toolchain rights remain separate.

## Primary sources

1. <https://github.com/isledecomp/isle/blob/8119bd013645972c72480e4de21529f1e91ce5c7/README.md>
2. <https://github.com/isledecomp/isle/blob/8119bd013645972c72480e4de21529f1e91ce5c7/CMakeLists.txt>
3. <https://github.com/isledecomp/isle/blob/8119bd013645972c72480e4de21529f1e91ce5c7/LICENSE>

## More in Games

- [Majora’s Mask: matching US N64 decompilation](https://awesomerea.org/resources/zelda-mm-decomp-case/index.md) · Case study
- [Mario Kart Wii: an in-progress matching decompilation of the PAL release](https://awesomerea.org/resources/mario-kart-wii-decomp-case/index.md) · Case study
- [Mario Kart: Double Dash!!: a matching GameCube decompilation of the debug build](https://awesomerea.org/resources/mario-kart-double-dash-decomp-case/index.md) · Case study
- [Mario Party 4: matching GameCube decompilation of the USA releases](https://awesomerea.org/resources/mario-party-4-decomp-case/index.md) · Case study
- [MediEvil decompilation: an early checksum-gated PlayStation project](https://awesomerea.org/resources/medievil-decomp-case/index.md) · Case study
- [Metroid Prime: the PrimeDecomp matching GameCube decompilation](https://awesomerea.org/resources/primedecomp-metroid-prime-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.