Chameleon Ultra — Firmware and Open-Source Ecosystem

Stub — section skeleton authored 2026-06-27; prose to follow.

9.1 Contents

1. The open-source story
2. Firmware repository layout [VERIFY]
3. Release cadence and version numbering [VERIFY]
4. OTA update via ChameleonUltraGUI
5. USB DFU update [VERIFY]
6. Building from source — toolchain requirements [VERIFY]
7. Community forks and third-party firmware variants [VERIFY]
8. Contributing upstream
9. What changes between firmware versions — tracking the changelog

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9.2 The open-source story

Note the RRG/Proxgrind dual provenance: the same group that maintains the Proxmark3 Iceman fork; explain how the Chameleon Ultra firmware emerged from that research culture and what GPL-3.0 means for auditability and community trust. Cross-link: ../../Proxmark3 RDV4/CLAUDE.md.

9.3 Firmware repository layout [VERIFY: current repo structure at https://github.com/RfidResearchGroup/ChameleonUltra]

Walk the top-level directory tree of the GitHub repo — firmware source, application layer, tooling, documentation — so a reader opening the repo for the first time knows where each concern lives.

9.4 Release cadence and version numbering [VERIFY]

Describe how RRG tags releases, what the version string format means, and approximately how frequently stable releases ship; flag whether there is a semantic-versioning or rolling-release model.

9.5 OTA update via ChameleonUltraGUI

Step-by-step: open the GUI, navigate to the update panel, trigger the OTA download and flash, verify the new version string; note any pre-conditions (battery level, BLE stability).

9.6 USB DFU update [VERIFY: exact DFU entry procedure]

Describe the USB DFU fallback path for devices that cannot complete OTA — how to put the nRF52840 into DFU mode, what host-side tool (nrfutil or similar) is required, and how to flash a .zip or .bin package.

9.7 Building from source — toolchain requirements [VERIFY]

List the required toolchain: compiler (GCC ARM or LLVM), nRF5 SDK version, Nordic command-line tools, any Zephyr RTOS dependency, and the build invocation; note which host OSes are supported.

9.8 Community forks and third-party firmware variants [VERIFY: known forks as of mid-2026]

Survey known community forks — names, the feature set they add or change relative to mainline, and their maintenance status; flag which are considered stable and which are experimental.

9.9 Contributing upstream

Summarize the contribution workflow: fork → branch → PR → review cycle; note any CLA requirement, coding-style guidance, or CI gate that contributors must pass before a PR is merged.

9.10 What changes between firmware versions — tracking the changelog

Explain how to read the changelog or GitHub releases page to identify capability additions (new protocol emulation, new attack modes, UI changes) that affect field workflows; note any version-specific gotchas known at the time of authoring.