Hi,
I am trying to update nRF5340 netcore application, but i don't know how to start.
Here is what i tried:
1. I created two custom applications for nRF5340 appcore and netcore. Very simple, just print the compile time. Appcore additionally has the function of enter the DFU mode.
2. In my appcore application, it has one child image named "MCUboot", and the other child image named "netcore". Looks like this as follow:

Note:
- mcuboot_primary: is appcore application running location.
- mcuboot_secondary: is appcore application upgrading location.
- mcuboot_primary_1: is netcore application transmission location.
- mcuboot_secondary_1: is netcore application upgrading location.
3. I flash appcore upgrading package to ''mcuboot_secondary", and call 'boot_request_upgrade_multi(0, BOOT_UPGRADE_TEST)' in my appcore application.
After reboot, the appcore application can upgrading, but can not reverse. In addition, appcore application confirmed image by 'boot_write_img_confirmed_multi(0)'.
4. I try to flash netcore upgrading package to "mcuboot_secondary_1", and call 'boot_request_upgrade_multi(1, BOOT_UPGRADE_TEST)' in my appcore application.
But the netcore application can not upgrading after reboot.
What did i miss?
Best regards,
Yang Hu