Siging image for OTA DFU

RE: Siging image for OTA DFU

Sigurd — Mon, 12 Sep 2022 14:45:22 GMT

[quote user="EricHDS"]But, given that I would like to do the signing as a separate operation outside the normal build process; how would I do it in the "Windows nRF SDK" environment ?[/quote]

This page here might help you do that, https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.0.2/mcuboot/imgtool.html , but I think it would be easier to use the CONFIG_BOOT_SIGNATURE_KEY_FILE in the configuration file for the mcuboot child image approach.

RE: Siging image for OTA DFU

Eric Wiebols — Fri, 09 Sep 2022 14:41:24 GMT

Hi,

Since the previous (Linux) developer used some comand line script to do the signing as a stand-alone operation I suspect that the project is not properly set-up for "multi image". I.e. as I understand it there should be a child_image folder next to the src folder. In other words; no I have not added CONFIG_BOOT_SIGNATURE_KEY_FILE in the configuration file for the mcuboot child image, only in the regular prj.conf file. I guess this explains why mykey.pem is totally ignored in the build process. But, given that I would like to do the signing as a separate operation outside the normal build process; how would I do it in the "Windows nRF SDK" environment ?

\Eric

RE: Siging image for OTA DFU

Sigurd — Thu, 08 Sep 2022 14:55:26 GMT

Hi,

[quote user=""]So I add CONFIG_BOOT_SIGNATURE_KEY_FILE="d:/mykey.pem" and do a "clean build". Problem is that the build succeeds regardless if mykey.pem is present or not, i.e. if the USB stick is inserted or not. [/quote]

So did you put CONFIG_BOOT_SIGNATURE_KEY_FILE in the configuration file for the mcuboot child image?

Take a look at how nrf_desktop does it here: https://github.com/nrfconnect/sdk-nrf/blob/main/applications/nrf_desktop/configuration/nrf52820dongle_nrf52820/child_image/mcuboot/prj_release.conf

If you still have issues with this, try adding CONFIG_BOOT_SIGNATURE_KEY_FILE in both prj.conf and in child_image/mcuboot.conf

And if you still are having issues after that, could you post your build log here?