# rytm-fw-re: reconstructing Analog Rytm MKII firmware

> rytm-fw-re analyses the Elektron Analog Rytm MKII OS 1.74 update and builds a freestanding ColdFire replacement firmware wrapped as a flashable .syx file. Its Ghidra probes and notes cover the ELE3 container, bootstrap entry contract, memory map, display byte protocol and flash path. The author reports that the current replacement boots and displays a test pattern.

- Type: Case study
- Targets: Firmware · Protocol
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-06
- Added to the catalog: 2026-11-08
- Original resource: <https://github.com/ethernet8023/rytm-fw-re>
- Primary source: <https://github.com/ethernet8023/rytm-fw-re/blob/2f7f0c4c01da3433e6386774416ea33f6c3753af/README.md>
- Catalog page: <https://awesomerea.org/resources/rytm-fw-re-case/>
- Record JSON: <https://awesomerea.org/resources/rytm-fw-re-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/rytm-fw-re-case/index.md)

## Requirements & limits

- **Prerequisites:** Reproducing the analysis and hardware checks requires a separately obtained stock OS 1.74 update and an Analog Rytm MKII unit.
- **Prerequisites:** The firmware build uses a nixpkgs m68k cross compiler and invokes ld.bfd directly.
- **Limits:** The replacement OS currently stops after displaying a test pattern; the USB reflash path remains a plan.
- **License:** No licence file in the repository.

## Primary sources

1. <https://github.com/ethernet8023/rytm-fw-re/blob/2f7f0c4c01da3433e6386774416ea33f6c3753af/README.md>
2. <https://github.com/ethernet8023/rytm-fw-re/blob/2f7f0c4c01da3433e6386774416ea33f6c3753af/docs/display-protocol.md>
3. <https://github.com/ethernet8023/rytm-fw-re/blob/2f7f0c4c01da3433e6386774416ea33f6c3753af/STATUS.md>

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## 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.