Bootloader sample doesn't work for nRF52840 dk

[matan_spada]

I'm trying to flash the Bootloader sample to my nRF52840 
(in order to understand how dfu and ota works).

First I connected the usb cable to the board (at the top of the board) and flashed the sample.

Then I tried to follow the steps here and then to test it with the instructions here and it didn't work.

What exacly should I do after flashing the sample?

I would appreciate if someone can write the steps as simple as it can be or any other usefull advice.

Thanks!

[Amanda Hsieh]

Hi, 

The nRF Secure Immutable Bootloader cannot build and run without an application. 

Please refer to https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.2.0/nrf/samples/bootloader/README.html#building-and-running-using-vsc to add the NSIB as a child image to your application. 

Regards,
Amanda H.

[matan_spada]

Thanks. 

Even though I already followed these steps, for some reason now it works. 

And on the same topic, is there an nRF bootloader that can be build and run without an app?
And what is the purpose and use of the bootloader sample?

[Amanda Hsieh]

matan_spada said:

is there an nRF bootloader that can be build and run without an app?

No, it cannot run without an application. 

matan_spada said:

what is the purpose and use of the bootloader sample?

Check out the nRF Secure Immutable Bootloader and Architecture.

-Amanda H.