nRF52832 b0+mcuboot+app

Question

Hi, 
 
 Trying to structure image in the following way: 
 b0 
 mcuboot 1 
 mcuboot 2 
 app 
 
 With the following setup: 
 App prj.conf: 
 ``` 
 
 CONFIG_BOOTLOADER_MCUBOOT =y 
 
 CONFIG_SECURE_BOOT =y 
 CONFIG_SB_SIGNING_KEY_FILE = "nsib_priv.pem" 
 
 ``` 
 
 ./child_image/mcuboot.conf: 
 ``` 
 
 CONFIG_SIZE_OPTIMIZATIONS =y 
 CONFIG_SINGLE_APPLICATION_SLOT =y 
 
 CONFIG_MCUBOOT_SERIAL =y 
 CONFIG_UART_CONSOLE =n 
 
 CONFIG_MCUBOOT_INDICATION_LED =y 
 
 `` 
 building return error: 
 ``` 
 warning: UPDATEABLE_IMAGE_NUMBER (defined at /home/ab/ncs/v2.6.0/bootloader/mcuboot/boot/zephyr/Kconfig:596, /home/ab/ncs/v2.6.0/nrf/samples/common/mcumgr_bt_ota_dfu/Kconfig:89, subsys/dfu/Kconfig:88) was assigned the value '2' but got the value '1'. See docs.zephyrproject.org/.../kconfig.html and/or look up UPDATEABLE_IMAGE_NUMBER in the menuconfig/guiconfig interface. The Application Development Primer, Setting Configuration Values, and Kconfig - Tips and Best Practices sections of the manual might be helpful too. 
 warning: user value 2 on the int symbol UPDATEABLE_IMAGE_NUMBER (defined at /home/ab/ncs/v2.6.0/bootloader/mcuboot/boot/zephyr/Kconfig:596, /home/ab/ncs/v2.6.0/nrf/samples/common/mcumgr_bt_ota_dfu/Kconfig:89, subsys/dfu/Kconfig:88) ignored due to being outside the active range ([1, 1]) -- falling back on defaults 
 error: Aborting due to Kconfig warnings 
 ``` 
 
 Please help to resolve the issue