How to switch to bootloader dfu mode when the program run in an app?

[oplinux]

Hi guys:

  a. I use a uart dfu bootloader(loacation: SDK-location\nRF5_SDK_15.0.0_a53641a\nRF5_SDK_15.0.0_a53641a\examples\dfu\secure_bootloader\pca10056_uart) in 52840 soc.

  b.I flashed the bootloader and SoftDevice by nrfjprog firstly.(cmd: nrfjprog -f NRF52 --program boot.hex)

  c.Then, I upload app.zip package by nrfutil.(cmd: nrfutil  dfu serial -pkg test-dfu15.zip -p COM16 ), the app is SDK-location\nRF5_SDK_15.0.0_a53641a\nRF5_SDK_15.0.0_a53641a\examples\ble_peripheral\ble_app_uart.

  I want to switch to bootloader dfu mode to get the newer firmware in ble_app_uart. Which API can i used? Can you give me an example.

  My ble_app_uart connected to a mobile. When I receive a command(eg: a string "update") from the mobile. the 52840-DK enter dfu mode right  away. How to achieve this function?

  Thanks.

    

[Einar Thorsrud]

Hi,

To enter DFU mode from the app you need to ensure that the sdk_config.h of the bootloader has NRF_BL_DFU_ENTER_METHOD_GPREGRET set to 1. The, just write a magic word () to the retention register and reset, as described in this post.