# Siemens MS42 and MS43: Reverse engineered Siemens MS42 and MS43 engine control units with a C167 toolchain > Source: > Published: 2026-10-30 19:30:58+00:00 ## Evidence at a glance Loading source evidence… ## What was done This project provides a C167 toolchain for Siemens MS42 and MS43 engine control units, featuring a disassembler, assembler, emulator, and image checker. It includes documentation and automated tests for 34 stock images. The [MS4X](https://raw.githubusercontent.com/therudywolf/ms4x/HEAD/README.md) repository provides reverse engineering tools and documentation for the Siemens MS42 (0110C6) and MS43 (430069) engine control units used in BMW vehicles. The project includes a C167 toolchain consisting of a disassembler, assembler, and code walker, alongside an emulator for the C166 instruction set. An image checker tool identifies program contents, checksums, and patch status within binary dumps. The author reports that AI tools were used for parts of the disassembly, cross-checking, and writing. Every number is verified against binaries, and the tools are tested against 34 stock images. The repository is currently in a paused state as of 30 October 2026, though existing code and tests remain maintained. The project does not include firmware dumps, immobilizer data, or factory protection bypasses. ## Community Ask a question, share what worked, or follow the next milestone. [Your library](https://reversedwithai.com/library)