What is the main reason that the MBR (0x7E) page is being to protected mode when the bootloader starts?

[attila-v]

I have to write this page in case of the application firmware update, so I have to unprotect it in the bootloader (in the nrf_bootloader_app_start_final() function).
won't this be a problem?

regards,
Attila

nRF52832, SDK 15.3

[attila-v]

hi,

I had a little time to deal with this issue.

Main experience is, that if I set NRF_DFU_IN_APP to 1, the ble-dfu-secure bootloader could not start, it stops at the beginning. There is no such problem with iot-secure bootloader.

so while I need the possibility of the ble-dfu too, is there any other settings in the sdk_config.h, which I must to set for the good working?

regards, Attila

[Hung Bui]

NRF_DFU_IN_APP is not supposed to be used with the bootloader. You define this when you want to use the bootloader modules, foe example dfu_settings.c in your application. 

Doing background DFU requires you to have a deep understanding of how the bootloader and the DFU process works, before you start integrate background DFU into your application. I would suggest to study the bootloader as much as possible. 

We do have an example for doing background DFU, please have a look at this thread: https://devzone.nordicsemi.com/f/nordic-q-a/46994/background-dfu-application-source-code