SDK 16 nRF52840 Buttonless DFU - How to debug the app

RE: SDK 16 nRF52840 Buttonless DFU - How to debug the app

Nikosant03 — Fri, 22 Apr 2022 13:27:09 GMT

That's clear!! Thank you a lot 🙂

RE: SDK 16 nRF52840 Buttonless DFU - How to debug the app

Hung Bui — Fri, 22 Apr 2022 13:19:59 GMT

Hi Nikos,

No, the bootloader and bootloader setting is located at different place from the application. See the memory layout here.

When you do "build and run" or "build and debug" SES will only erase the area that the application occupied and leave the other area untouched.

If you want to erase the entire chip please follow the commands here: https://infocenter.nordicsemi.com/topic/ug_gsg_ses/UG/gsg/erase_board_ses.html?cp=1_0_2_6_0

RE: SDK 16 nRF52840 Buttonless DFU - How to debug the app

Nikosant03 — Fri, 22 Apr 2022 10:38:16 GMT

Thank you Hung,

When we update the app and download it to the target through "Build and Debug" or "Build and Run", why we do not need to flash the bootloader and the settings again?

I mean, we flash the bootloader and the settings during the first time flashing through nrfjprog. When we update or debug the app through SES, the bootloader and the settings are not erased from the memory?

RE: SDK 16 nRF52840 Buttonless DFU - How to debug the app

Hung Bui — Tue, 19 Apr 2022 08:18:22 GMT

Hi Nikos,
Yes it's the correct sequence for an image to be used in an end product. Please don't forget to remove the modification that I suggested in previous reply after you are done with the development.

RE: SDK 16 nRF52840 Buttonless DFU - How to debug the app

Nikosant03 — Thu, 14 Apr 2022 08:51:30 GMT

Thank you Hung,

I went through modifying nrf_bootloader.c and it works fine. Could you please verify the following step sequence to perform buttonless OTA DFU?

First time flashing:

1. Build the app

2. Generate the bootloader settings

3. Merge and flash app + settings + bootloader + sd

If I want to update the firmware:

1. Update and build the firmware

2. Generate the .zip file

3. Start secure DFU

This is the correct sequence?

RE: SDK 16 nRF52840 Buttonless DFU - How to debug the app

Hung Bui — Fri, 25 Mar 2022 12:03:31 GMT

Hi Nikos,

If you are developing your application and need to update the application, you can modify the dfu_enter_check() in the nrf_bootloader.c to remove the CRC check on each boot:

If you comment out this or change it to return false then the bootloader will enter the app regardless if it's been modified and flashed via the debugger/programmer.

After this modification, you can just flash both bootloader and application to the flash. Then you can modify and debug the application as normal.

Another option is to autogenerate a bootloader setting that matched with your new app. Then flash both the app and the bootloader setting via the debugger/programmer.