Instructions are originally from: https://www.zigbee2mqtt.io/information/flashing_the_cc2531.html
### Windows
1. Download and install the "SmartRF Flash Programmer" **(Not v2)** application from https://www.ti.com/tool/FLASH-PROGRAMMER
2. Connect CC debugger to the CC2531 USB sniffer.
3. Connect **BOTH** the CC2531 USB sniffer and the CC debugger to your PC using USB.
* If the light on the CC debugger is RED press set reset button on the CC debugger. The light on the CC debugger should now turn GREEN. If not use [CC debugger user guide](http://www.ti.com/lit/ug/swru197h/swru197h.pdf) to troubleshoot your problem.
4. Download the firmware [CC2531_DEFAULT_20190608.zip](https://github.com/Koenkk/Z-Stack-firmware/raw/master/coordinator/Z-Stack_Home_1.2/bin/default/CC2531_DEFAULT_20190608.zip)
4. Start SmartRF Flash Programmer, with the properties below:
* Flash image: Make sure to select the .hex file and not the .bin file.
* Uncheck "Retain IEEE address when reprogramming the chip.
### Linux or MacOS
1. Install prerequisites for CC-Tool using a package manager (e.g. Homebrew for macOS)
3. Connect **BOTH** the CC2531 USB sniffer and the CC debugger to your PC using USB.
* If the light on the CC debugger is RED press set reset button on the CC debugger. The light on the CC debugger should now turn GREEN. If not use [CC debugger user guide](http://www.ti.com/lit/ug/swru197h/swru197h.pdf) to troubleshoot your problem.
4. Download the firmware [CC2531_DEFAULT_20190608.zip](https://github.com/Koenkk/Z-Stack-firmware/raw/master/coordinator/Z-Stack_Home_1.2/bin/default/CC2531_DEFAULT_20190608.zip)