ChameleonUltra and ChameleonLite both support DFU Mode – Device Firmware Upgrade Mode. Based on NRF52840 chip, they can be operated with Both USB and bluetooth connection. Here’s a simple tutorial for upgrade th firmware of ChameleonUltra with only Bluetooth.
Preparation
Install DFU App
nRF Device Firmware Update is a mobile app for updating nRF5 SDK firmware using Bluetooth Low Energy as a transport.

Download the latest zip
package of your ChameleonUltra or ChameleonLite.
RfidResearchGroup/ChameleonUltra

Steps
- Enter the DFU Mode There are 2 ways to enter DFU Mode
Option 1: Connect ChameleonUltra in MTools Lite and clickEnter DFU Mode
.
Option 2: Hold on Button B and plugin USB Cable. Once get in DFU Mode, you can see the two LEDs in the middle blinking alternately. - Choose firmware file in DFU App.
- Select Bluetooth devces whose name starts with
CU-
. - Click
Upload
button to upload and upgrade the frimware. - Wait for 1 mins to click Button A to power on ChameleonUltra again.

Fimware
dfu-app.zip
– The firmware only includes application parts.
dfu-full.zip
– The firmware includes both application and bootloader.
Choose ultra-dfu-app.zip
or lite-dfu-app.zip
depending on your devices.