The Secure Device Firmware Update (DFU) Service exposes necessary information to perform Device Firmware Updates on the device. This service is a proprietary service defined by Nordic Semiconductor to demonstrate a typical Device Firmware Update on an nRF5 device.

The USB Secure Device Firmware Update (DFU) uses CDC ACM USB class, commonly known as Virtual COM port. After connecting the USB cable, the development kit will enumerate as a COMx port on Windows hosts or as a /dev/ttyACMx device on Linux/Unix hosts. The port can be opened and closed just like a traditional serial port. Refer to sdk_app_usb_dfu_bootloader for driver installation instructions.

The firmware can be transferred using the same packet encoding used for Serial.