DFU over a serial UART connection

This DFU method uses a serial UART connection for the Device Firmware Update (DFU).

Most Nordic Semiconductor Development Kits (DKs) have an interface MCU that serves as a virtual COM port and transparently maps the UART into a USB CDC ACM interface. See Virtual COM port for more information.

If no interface MCU is available, use other options to connect the DFU target to your computer, such as a USB to TTL adapter or a serial cable with an RS-232 connector.

Related nRF5 SDK documentation

• Secure DFU Bootloader over Serial Link (UART/USB) Example

You can run the nrfutil nrf5sdk-tools dfu serial command to perform this update, together with appropriate options for your setup. To see the list of options, run the nrfutil nrf5sdk-tools dfu serial --help command.

Complete the following steps to perform the DFU:

1. Connect the DFU target to your computer.

2. Run nrfutil nrf5sdk-tools dfu serial with appropriate options to perform DFU over a serial UART connection.

   For example, enter the following command to perform a DFU procedure of the file app_dfu_package.zip over COM3 at 115200 bits per second:

   nrfutil nrf5sdk-tools dfu serial --package app_dfu_package.zip --port COM3 --baud-rate 115200
   

   In this command:

   • --package specifies the package to be transferred.
   • --port specifies the serial port to which the DFU target is connected.
   • --baud-rate specifies the baud rate for the serial connection.