Creating a bootable first article hex image for nrf52840 based hardware.

[habibfarahani]

I am using SDK 15.3.0 and need to create a single hex file to program the initial batch of our nRF52840 based HW.
Currently, I have built the bootloader project (open not secure for now) and have a bootloader.hex file.

1. As a first step I created the bootloader settings file by:

nrfutil settings generate --family NRF52840 --application app_pca10056_s140.hex --application-version 0 --bootloader-version 0 --bl-settings-version 2 setting.hex

2. Merged bootloader hex file with setting (Apparently mergehex has a limit on number of input files to merge)

mergehex -m bootloader.hex setting.hex -o final-boot.hex

3. Merged the APP + SD + BL

mergehex -m app_pca10056_s140.hex s140_nrf52_6.1.1_softdevice.hex final-boot.hex -o firstArticle.hex

4. When I use nrfjprog to erasend program firstArticle.hex, nothing happens and the system is completely dead:

nrfjprog --family nRF52 --eraseall
nrfjprog --family nRF52 --program firstArticle.hex

However, If I go back to SEGGER and launch debugger for the bootloader (the one I used hex file for the above steps), the system boots and all is happy.

Can someone point me to what I am doing wrong? For now I am not using secure boot.

[Edvin]

Hopefully, the only thing you forgot is to reset the device after you programmed it. I guess if you power cycle it, it will boot up. At least if it boots up with the same hex when you debug.

Try:

nrfjprog --eraseall
nrfjprog --program firstArticle.hex --verify
nrfjprog --reset

Note that you don't need the --family input in the later versions of nrfjprog, and that I added --verify after the program command. I recommend you use this when you program hex files. Usually everything works well without, but if there for some reason is some communication errors, this will be detected by the --verify.

Best regards,

Edvin

[habibfarahani]

Thanks Edvin,  I was pushing the reset button on the board.  Upon power cycle it all worked out.

[Edvin]

Yes. That makes sense. The reset button behavior is written in SW, but it requires a reset before the changes takes place. You can either do this first reset through the programmer (reset command) or you can power cycle it. After this, the reset button should work as expected.

BR,

Edvin