SDK 16 nRF52840 Buttonless DFU - How to debug the app

Question

Hi guys, 
 I am experimenting with OTA buttonless DFU. 
 I included the Buttonless Secure DFU Service to my application and I managed to flash the new image over the air through buttonless DFU 
 Now, what if I want to include new features in my application and debug it? I can't just build and debug the application because it requires the secure bootloader to be flashed. 
 How can I work around this?

Hung Bui · Accepted Answer

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

Hung Bui · Answer

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.

Hung Bui · Answer

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.

SDK 16 nRF52840 Buttonless DFU - How to debug the app

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