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Flash Firmware using JelmerT's serial bootload tool

JelmerT's serial bootload tool is a cross-platform Python script that allows you to flash firmware on TI's newer chips.

All ZigStar boards are supported by


Option 1:

Use the precompiled exe file cc2538-bsl.exe. You do not need to install python and required modules. Go straight to Step 2.

Option 2:

  • Install python
  • Use python --version to be sure, that you are running python 3 or above!
  • If you are NOT running 3.4 or higher, you need to install pip, too.
  • Install dependencies with pip install pyserial intelhex
  • Download the [] file or just clone the repo.

Copy and paste the command into your terminal.

sudo apt update && sudo apt-get install python3-pip
wget -O && unzip
sudo pip3 install pyserial intelhex

Python3 should already be shipped with macOS,if no then follow below procedure:

Download and extract cc2538-bsl:

curl --output && unzip
Install required dependencies:
/usr/bin/python3 -m pip install --user pyserial intelhex

Download Python for Windows and install. After installation verify Python if its installed by running python -V in Command Prompt.

If you receive a message similar to Python is not recognized as an internal or external command, operable program or batch file., this means Python is either not installed or the system variable PATH hasn’t been set. You’ll need to launch Python from the folder in which it is installed or adjust your system variables to allow it to be launched from any location.

Download the zipped code and extract to a folder.

Install required dependencies:

pip install pyserial intelhex


Please use the Power Shell to have the best user experience. If you encounter permissions issues, ensure that you are running your terminal as an administrator.

Determine the USB port/ IP address

Plug your device in and ensure that device is recognised by your OS:

On linux, use this:

ls -l /dev/serial/by-id
Issue dmesg and observe the device enumeration:

[152343.203201] usb 1-1.4: new full-speed USB device number 5 using dwc_otg
[152343.336384] usb 1-1.4: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.62
[152343.336400] usb 1-1.4: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[152343.336409] usb 1-1.4: Product: USB2.0-Serial
[152343.338315] ch341 1-1.4:1.0: ch341-uart converter detected
[152343.341440] usb 1-1.4: ch341-uart converter now attached to ttyUSB0

On macOS find the device using:

ls /dev/tty.* 
Issue dmesg and observe the device enumeration:
IOUserSerial::AppleUSBCHCOM::<private>: 127 0x6000013e4058
IOUserSerial::<private>: 456 0x6000013e4058
IOUserSerial::<private>: 41 0x6000013e4058
DK: AppleUSBCHCOM-0x1000030ea::start(IOUSBHostInterface-0x1000030e5) ok

On windows, use this in a Powershell or go to Device Manager

$comports = Get-WMIObject Win32_SerialPort; $comports | Get-PnpDeviceProperty -InstanceId {$_.pnpdeviceid} -Keyname DEVPKEY_Device_BusReportedDeviceDesc | ForEach-Object { foreach($comport in $comports) { if ($comport.pnpdeviceid -eq $_.instanceid) { new-object psobject -property  @{COMPORT = $comport.deviceid; 'Device-Name' = $} } } }
The drivers for CH340 should be automatically be picked up,check under "Ports (COM & LPT)" in Device Manager:

BSL Button

If you need to install the drivers manually, go HERE for official drivers.


Double-check by undocking the device again.


For network device find out IP or hostname.

Put your device in BSL mode

Please follow the following instructions to put your device in BSL mode:

  • Unplug your stick from the host
  • Press the BSL/FLASH pushbutton and keep holding while plugging the device back into the host

BSL Button BSL Button

  • Give it a few seconds for the device to settle and set up and release the BSL button
  • Your stick should now be in ROM bootloader mode

It's very important that you press and hold the BSL button before plugging it in to the host and release it after a few seconds.

Note and .exe supports "Auto-BSL", now you can skip the BSL pushbutton press for flashing boards.

Just follow normal firmware procedure using or cc2538-bsl.exe. ( Boards using CH340E does not support Auto-BSL! )

  • Access device by IP or hostname using your browser
  • Click Firmware Update initiate the bootloader (BSL) mode for the module:

BSL Button

  • Watch the Debug output and when promted go to next step.

BSL Button

Flash firmware

To flash firmware, run:

./cc2538-bsl.exe -p PORT -evw FIRMWARE
...where PORT is the serial port your board is connected to.
./cc2538-bsl.exe -p socket://ip_or_localdns_name:6638 -evw FIRMWARE

python -p PORT -evw FIRMWARE
...where PORT is the serial port your board is connected to
python -p socket://ip_or_localdns_name:6638 -evw FIRMWARE

(see above) and FIRMWARE is the hex file you want to flash (see here for help on choosing firmware).


-p: will select the port
-evw: will erase,write and check firmware


It is crucial that you download the correct firmware for your stick as using the wrong firmware will disable the BSL and you will need an external debugger / programmer to flash your stick again.


Erase device

To completely erase the device flash, run:

./cc2538-bsl.exe -p PORT -e
...where PORT is the serial port your board is connected to.
./cc2538-bsl.exe -p socket://ip_or_localdns_name:6638 -e

python -p PORT -e
...where PORT is the serial port your board is connected to.
python -p socket://ip_or_localdns_name:6638 -e

Clearing NVRAM

During the flashing process, the coordinator's memory (NVMEM) may contain arbitrary data, which may in some cases prevent NVMEM recovery from the backup.

The coordinator's memory is cleared by the zStackEraseAllNvMem.js script, which is usually located in this directory:

The command line will look something like this:
node zStackEraseAllNvMem.js /dev/ttyUSB0
node zStackEraseAllNvMem.js socket://ip_or_localdns_name:6638

Download and install zigpy-znp:

pip install zigpy-znp
Erase your device's NVRAM entries to fully reset it:
python -m /dev/serial/by-id/your-radio
python -m socket://ip_or_localdns_name:6638
Some warnings are normal, as not all entries will be present in every device.


At the end of the flashing, you may need to unplug-plug your device or press RST.

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