Hi there, we have many nRF52840 devices in the field that currently run firmware based on the nRF5 SDK. We'd like to port our codebase to the nRF Connect SDK for all new products, and would like to update existing devices via BLE DFU, so that we don't have to maintain 2 separate codebases moving forward.
I've seen several (older) threads on this topic, but it's not entirely clear to me if this is supported, or if it's even possible, as there is some conflicting information. From what I understand, it'd have to work something like this:
• patch and DFU the existing nRF5 SDK bootloader, so that it will continue booting an application even if it can't find the SoftDevice magic
• build the NCS based app with MCUBoot enabled, and put MCUBoot at an address where it doesn't interfere with the MBR or nRF5 SDK bootloader
• DFU the merged MCUBoot + NCS application, overwriting the SoftDevice
• the nRF5 SDK bootloader will boot, skip the SoftDevice signature check (because we patched it in step 1), then continue booting into MCUBoot
• future DFU's will be performed using MCUBoot
Does that sound about right? Has anyone been successful doing this with a recent release of the Nordic Connect SDK? It seems to me like this would be a relatively common request, as devices in the field running firmware based on the nRF5 SDK would eventually want to migrate over to firmware based on the Nordic Connect SDK.