nRF9160dk FOTA using external flash, ncs 2.0.2

Hi, 

I am using nRf9160dk with mcuboot secondary image on external flash base on AZURE_FOTA example, ncs 2.0.2.

Found the bootloader cannot runs primary image.

So, I need advice on how to set up the mcuboot secondary with SPI flash.

Checked the partition with west build -t partition_manager_report .

My configuration as follows:

child_image\mcuboot\boards\nrf9160dk_nrf9160_mcuboot.overlay

child_image\mcuboot\prj_mcuboot.conf

nrf9160dk_nrf9160_ns.overlay

pm_static.yml

prj.conf