ChameleonUltra Firmware — Open-Source nRF52840 NFC/RFID Firmware
GPL-3.0 licensed firmware for the ChameleonUltra built on the Nordic nRF52840 SDK. Handles dual-frequency card emulation, MIFARE cracking, BLE communication, and USB-C connectivity with a read-only bootloader preventing bricking.
ChameleonUltra Firmware
The ChameleonUltra firmware is the open-source C codebase that powers the ChameleonUltra NFC/RFID multi-tool. Built on the Nordic nRF52840 SDK, it handles everything from card emulation and MIFARE cryptographic attacks to BLE wireless communication and USB-C device management.
Key Features
- Dual-frequency emulation — 13.56 MHz (ISO 14443A) and 125 kHz (EM410x, T5577, HID Prox, Indala)
- Hardware-accelerated cracking — Darkside, Nested, StaticNested, and Hardnested attacks on MIFARE Classic
- 8+8 card slots — simultaneously store 8 HF and 8 LF card emulations
- BLE 5.0 wireless control — full device control from phone or PC
- Read-only bootloader — DFU mode with brick protection
- USB-C — firmware updates and charging
Building from Source
The firmware can be compiled using the Nordic nRF5 SDK and ARM GCC toolchain. Detailed build instructions are available in the GitHub wiki's development section.
Flashing
Flash via DFU using:
nrfutil device program --firmware objects/dfu-full.zip --traits nordicDfu
On Linux, convenience scripts flash-dfu-app.sh and flash-dfu-full.sh are provided. Firmware can also be flashed wirelessly over BLE using the ChameleonUltraGUI app.
Contributing
The firmware is GPL-3.0 licensed with an active community of contributors. Development discussions take place on the RFID Hacking community Discord server in the Software/chameleon-dev channel.
