Read network core app version from app core (nRF5340, v2.6.1) to confirm successful update

[responsible_duck]

Hello,

We tried using pcd_network_core_app_version() to read the network core version (presumably set by CONFIG_FW_INFO_FIRMWARE_VERSION in our hci_ipc.conf) from the app core. To do this, we set the following flags to the app core prj.conf:

CONFIG_PCD=y
CONFIG_PCD_APP=y
CONFIG_FW_INFO=y
CONFIG_PCD_READ_NETCORE_APP_VERSION=y

However, we got a build error: "/opt/nordic/ncs/v2.6.1/zephyr/subsys/dfu/boot/mcuboot.c:23:10: fatal error: zephyr/fw_info.h: No such file or directory" 

Went in mcuboot.c and updated the include to: #include <fw_info.h>. Now it builds. But it does not run. 

Is there an example out there of how to do this properly?

Thanks,

Ever

[Hung Bui]

Hi Ever, 

I was checking a little bit internally. It seems that it's not possible to read the net core image version from the application on app core. It's possible to do so from the MCUBoot but not from the app. 
This has been asked before: NRF5340 GET NETCORE FW_INFO FROM APPCORE

The reason for that is that the B0n doesn't run when the application is running. It's only run when MCUBoot running and that when MCUBoot can communicate with B0n via PCD library.

Please be aware that the downgrade avoidance feature is available by default in MCUBoot. My assumption is that you want to read the netcore version to avoid having to download old image version ? 

One workaround I can think of is to modify MCUBoot to read the image version on each boot and find away to send that to the application, for example via writing to flash or RAM.