DFU OTA within NRF Connect SDK using bluetooth, a smartphone and an nRF52840dk or an nRF52833dk

[Guglielmo]

Dear Nordic, 

Let's say I have a blinky application altready flashed on a dk board that blinks one of the four leds.

I am trying to figure out how to build an application so that when I flash this application on the board using bluetooth from my smartphone it lights another led.  This is one of the simplest DFU update I can think about it.

I spent following your guide step by step but I don't find it really clear and I didn't managed to get anything working.

Developing with nRF52 Series — nRF Connect SDK 2.3.0 documentation (nordicsemi.com)

Can you please tell me if I have to code the first blinky application in a specific way so that it already broadcasts via bluetooth that the dk board can be updated?

Please I need to know all the steps you would take in order to successfully perform a DFU over the air using the nrf connect sdk, a smartphone and a development kit board.

Also, I am already familiar with zephyr and most of the tools and apps you provide: nRF Connect, nRF Toolbox, the Visual Studio code's plugin (nRF Connect)

[AHaug]

Hi,

You could use https://github.com/nrfconnect/sdk-mcuboot/blob/d5d451ec21d749f7bc09910f7c426f332c557900/boot/zephyr/Kconfig#L501 to indicate that the device is in bootloader mode. Do note that this is not the same as a "DFU LED", which is something that you will have to add as a proprietary solution in your DFU procedure. I suggest using the bootloader led I linked instead.

Please I need to know all the steps you would take in order to successfully perform a DFU over the air using the nrf connect sdk, a smartphone and a development kit board.

This is a very general question which is best answered by suggesting these samples, docs and that you thoroughly investigate them. Start at the top with a repo containing theory that breaks down the abstraction quite well and showcases how a simple SMP server can be used to perform DFU over BLE with a mobile phone and then move further down.

1. Smp samples from this unofficial git repo https://github.com/hellesvik-nordic/samples_for_nrf_connect_sdk/tree/main/bootloader_samples/smp (do note that it only works up to v2.2.0 and v2.3.0 requires some changes)
2. Smp server sample from Zephyr https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/samples/subsys/mgmt/mcumgr/smp_svr/README.html
3. In addition to "working with 52 series" which you linked, you should have a look at https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.3.0/nrf/app_dev/bootloaders_and_dfu/index.html
4. Learn about partitioning and static partition through the Partition manager: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/scripts/partition_manager/partition_manager.html
   
   1.  nrf5340 multi-image DFU update over BLE 'Remote Error: In Value(3)' ? this case might showcase the importance of static partitioning, specially if you intend to migrate to newer versions in NCS in the future
      

In addition I would like to recommend

1. Lesson 2 in https://academy.nordicsemi.com/courses/nrf-connect-sdk-fundamentals/ for more about how to toggle and use LEDS in general (and maybe also the rest if you're relatively new to NCS) if you intend to add the DFU LED instead of the Bootloader-mode LED I suggested
2. In case you're new to BLE: https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/ 

Kind regards,
Andreas