Merge firmware .hex with DFU Key

[AmiguelS]

Hello!

During the development phase, we have been flashing our nRF52 devices directly (though the debugger) and with no signing keys. We have also tested flashing the devices over the air (now with signing keys), because it can be very convenient.

We now require a faster method to flash our complete firmware to the devices, without using bluetooth.

I had a look at this answer and tried several configurations and possibilities, but with no success. I was able to flash a version of the firmware, but the bootloader never boots the application, and keeps waiting to be flashed over the air. It also seems that our specific case is not covered by the answers (keys...).

Our firmware contains the Signed Bootloader + Softdevice + App. I believe the presence of the signed bootloader is what may be causing the described methods to fail.

What procedure should be followed to merge the complete firmware?

We are using a nRF52832 with S132 (SDK 12.3.0).

Thanks!

[Vidar Berg]

Hello,

The thread you linked to explained how to generate the settings page for the old bootloader, but this approach has changed for the new secure bootloader. Please refer to Appendix 1 in this blog post for instructions on how to generate and merge the setttings page: https://devzone.nordicsemi.com/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader  

[AmiguelS]

Hello!

Could you please clarify what procedure should be followed to merge the complete .hex (using the settings page generated from the link you mentioned)? Is the procedure the same when using gcc?

Thanks.

[Vidar Berg]

Hi, documentation for the "mergehex" tool can be found here: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.tools/dita/tools/nrf5x_command_line_tools/nrf5x_mergehex.html?cp=5_1_2. The procedure is the same regardless of toolchain.

e.g.,

mergehex -m APPLICATION.hex SETTINGS.hex BOOTLOADER.hex -o APPBL.hex // mergetool can merge 3 hex files at a time.

mergehex -m APPBL.hex SOFTDEVICE -o FINAL.hex

[AmiguelS]

Hello, I'm sorry for insisting on this, but I'd just like to confirm that the order App > Settings > Bootloader > Softdevice is the correct one. Although I'm able to merge all the files and flash them, there is no device boot. Not event the bootloader starts...

[Vidar Berg]

Hello, the order doesn't matter when you merge hex files. Are you able to share your merged hex files so I can try it here. Alternatively, read out the cpu registers, it may give an indication on where and why it fails. You can use the --readregs option in nrfjprog for this: nrfjprog --readregs