Merging Different Hex Files (Sysbuild)

[Amira R.]

Hello, 

I'm working on an application using NCS v3.1.1 using the NSIB and MCUboot as its bootloader chain. The application was formerly on NCS v2.9 and I was wondering if it's possible to take a pre-built hex of MCUboot from the old build and use mergehex to make a custom merged.hex, mixing the versions? 

Would that yield the desired result of an older version of MCUboot running with the new application? If possible, which hex files would I need to combine (e.g. zephyr.signed.hex)?

Thank you!

[Simon D-M]

Hi,

It is theoretically it is possible to merge the hex together, but I would recommend to not do it.

There has been a major NCS version change, and we don't give any guarantee that the old MCUboot version will work with this more recent NCS version.

Best regards,

Simon

[Amira R.]

Hi Simon,

Thank you for getting back to me! I understand the compatibility concerns and am okay with the versions potentially not working together. I more so wanted better insight into the sysbuild building system and wanted to know if the merging step is something that can be done manually. 

[Simon D-M]

Hi,

It seems you can try to use "mergehex" (link) to merge them together. This tool is from an archived project (nRF command line tool) but I wasn't able to find any replacement in nRFUtil.

But again, I can't give any guarantee that it will work, so if you can please stick with the current version of MCUboot.

Best regards,

Simon