WARNING: Using default MCUBoot key, it should not be used for production

[snowuyl]

D:\ncs\v2.3.0\bootloader\mcuboot\samples\zephyr\hello-world>west build -b nrf5340dk_nrf5340_cpuapp
-- west build: generating a build system

..

=== child image mcuboot -  end ===

CMake Warning at D:/ncs/v2.3.0/nrf/modules/mcuboot/CMakeLists.txt:286 (message):


          ---------------------------------------------------------
          --- WARNING: Using default MCUBoot key, it should not ---
          --- be used for production.                           ---
          ---------------------------------------------------------

Procedures to reproduce this issue are as follows.

1. cd D:\ncs\v2.3.0\bootloader\mcuboot\samples\zephyr\hello-world

2. west build -b nrf5340dk_nrf5340_cpuapp

[Menon]

Hello,

When the default key for the MCUboot is used instead of your custom key, this warning will be seen. The devzone has had a lot of conversations related to this. Please try to look up similar topics. Additionally, you can take a look at this repository which talks about adding a custom key.

Kind Regards,

Abhijith

[snowuyl]

Thanks for your reply! I try to build the following sample. But it failed to build.

https://github.com/hellesvik-nordic/samples_for_nrf_connect_sdk/tree/main/bootloader_samples/keys_and_signatures/mcuboot_smp_custom_key

The following are log messages of west build.

D:\ncs\v2.4.0\bootloader\mcuboot\samples\zephyr\mcuboot_smp_custom_key>west build -b nrf5340dk_nrf5340_cpuapp
-- west build: generating a build system

...

warning: MCUMGR (defined at subsys/mgmt/mcumgr/Kconfig:5) was assigned the value 'y' but got the
value 'n'. Check these unsatisfied dependencies: NET_BUF (=n), ZCBOR (=n). See
docs.zephyrproject.org/.../kconfig.html and/or look up MCUMGR 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.

D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/prj.conf:3: warning: attempt to assign the value 'y' to the undefined symbol MCUMGR_SMP_UART

D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/prj.conf:4: warning: attempt to assign the value 'y' to the undefined symbol MCUMGR_CMD_IMG_MGMT
Parsing D:/ncs/v2.4.0/zephyr/Kconfig
Loaded configuration 'D:/ncs/v2.4.0/zephyr/boards/arm/nrf5340dk_nrf5340/nrf5340dk_nrf5340_cpuapp_defconfig'
Merged configuration 'D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/prj.conf'

error: Aborting due to Kconfig warnings

Procedures to reproduce this issue are as follows.

1. Unzipping mcuboot_smp_custom_key.zip to D:\ncs\v2.4.0\bootloader\mcuboot\samples\zephyr\ folder.

2. west build -b nrf5340dk_nrf5340_cpuapp

[snowuyl]

mcuboot_smp_custom_key.zip

[snowuyl]

Fullscreen Aborting_due_to_Kconfig_warnings.txt Download

D:\ncs\v2.4.0\bootloader\mcuboot\samples\zephyr\mcuboot_smp_custom_key>west build -b nrf5340dk_nrf5340_cpuapp
-- west build: generating a build system
Loading Zephyr default modules (Zephyr base).
-- Application: D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key
-- CMake version: 3.20.5
-- Using NCS Toolchain 2.4.0 for building. (D:/ncs/toolchains/31f4403e35/cmake)
-- Found Python3: D:/ncs/toolchains/31f4403e35/opt/bin/python.exe (found suitable exact version "3.8.2") found components: Interpreter
-- Cache files will be written to: D:/ncs/v2.4.0/zephyr/.cache
-- Zephyr version: 3.3.99 (D:/ncs/v2.4.0/zephyr)
-- Found west (found suitable version "1.0.0", minimum required is "0.7.1")
-- Board: nrf5340dk_nrf5340_cpuapp
-- Found host-tools: zephyr 0.16.0 (D:/ncs/toolchains/31f4403e35/opt/zephyr-sdk)
-- Found toolchain: zephyr 0.16.0 (D:/ncs/toolchains/31f4403e35/opt/zephyr-sdk)
-- Found Dtc: D:/ncs/toolchains/31f4403e35/opt/bin/dtc.exe (found suitable version "1.4.7", minimum required is "1.4.6")
-- Found BOARD.dts: D:/ncs/v2.4.0/zephyr/boards/arm/nrf5340dk_nrf5340/nrf5340dk_nrf5340_cpuapp.dts
-- Generated zephyr.dts: D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/build/zephyr/zephyr.dts
-- Generated devicetree_generated.h: D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/build/zephyr/include/generated/devicetree_generated.h
-- Including generated dts.cmake file: D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/build/zephyr/dts.cmake

warning: MCUMGR (defined at subsys/mgmt/mcumgr/Kconfig:5) was assigned the value 'y' but got the
value 'n'. Check these unsatisfied dependencies: NET_BUF (=n), ZCBOR (=n). See
http://docs.zephyrproject.org/latest/kconfig.html#CONFIG_MCUMGR and/or look up MCUMGR 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.


D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/prj.conf:3: warning: attempt to assign the value 'y' to the undefined symbol MCUMGR_SMP_UART

D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/prj.conf:4: warning: attempt to assign the value 'y' to the undefined symbol MCUMGR_CMD_IMG_MGMT
Parsing D:/ncs/v2.4.0/zephyr/Kconfig
Loaded configuration 'D:/ncs/v2.4.0/zephyr/boards/arm/nrf5340dk_nrf5340/nrf5340dk_nrf5340_cpuapp_defconfig'
Merged configuration 'D:/ncs/v2.4.0/bootloader/mcuboot/samples/zephyr/mcuboot_smp_custom_key/prj.conf'

error: Aborting due to Kconfig warnings

CMake Error at D:/ncs/v2.4.0/zephyr/cmake/modules/kconfig.cmake:339 (message):
  command failed with return code: 1
Call Stack (most recent call first):
  D:/ncs/v2.4.0/nrf/cmake/modules/kconfig.cmake:29 (include)
  D:/ncs/v2.4.0/zephyr/cmake/modules/zephyr_default.cmake:115 (include)
  D:/ncs/v2.4.0/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
  D:/ncs/v2.4.0/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
  CMakeLists.txt:7 (find_package)


-- Configuring incomplete, errors occurred!
FATAL ERROR: command exited with status 1: 'D:\ncs\toolchains\31f4403e35\opt\bin\cmake.EXE' '-DWEST_PYTHON=D:\ncs\toolchains\31f    f4403e35\opt\bin\python.exe' '-BD:\ncs\v2.4.0\bootloader\mcuboot\samples\zephyr\mcuboot_smp_custom_key\build' -GNinja -DBOARD=nrf5340dk_nrf5340_cpuapp '-SD:\ncs\v2.4.0\bootloader\mcuboot\samples\zephyr\mcuboot_smp_custom_key'

[snowuyl]

I found that there is no such warning message when I set CONFIG_BOOT_SIGNATURE_KEY_FILE to absolute path.

CONFIG_BOOT_SIGNATURE_KEY_FILE="D:/ncs/v2.4.0/bootloader/mcuboot/rsa2048_private.pem"

But there is warning message when I set CONFIG_BOOT_SIGNATURE_KEY_FILE to relative path.

CONFIG_BOOT_SIGNATURE_KEY_FILE="rsa2048_private.pem"