How to confirm image installed by MCU boot

[Torsten Robitzki]

Hi,

I still try to configure Nordic-Zepyr build for a nrf5340, with a BLE stack and MCUBoot as the bootloader. The application will receive image updates over MQTT and store them in external flash memory.

According to your documentation (https://docs.nordicsemi.com/bundle/ncs-latest/page/mcuboot/design.html), MCUBOOT_SWAP_USING_MOVE seems to be the state of the art algorithm for MCUBoot to install new images. I was able to get that up and running. Next step now, is to let the newly installed firmware confirm the installation, so that the bootloader will not rollback the installation with the next reset.

It looks like the necessary modifications of the image headers or trailers are implemented in `boot_write_img_confirmed()` to confirm the new image. 

How do I have to configure my application, so that I can use this library function? The `normal` CMake way seems to be straight forward and I would just have to add the bootutil library (defined in mcuboot/boot/bootutil/CMakeLists.txt) to my application target. With Zephyr, mcuboot/boot/bootutil/zephyr/CMakeLists.txt seems to apply here and it looks like I should add CONFIG_MCUBOOT_BOOTUTIL_LIB=y to my application configuration.

According to Kconfig.mcuboot:

menuconfig MCUBOOT_BOOTUTIL_LIB
	bool "MCUboot utility library"
	help
	  Enable MCUboot utility library which implements functions
	  required by the chain-loaded application and the MCUboot.

But, that does results in build error (complaining about CONFIG_BOOT_SWAP_USING_MOVE being not set), when compiling `bootloader/mcuboot/boot/bootutil/src/bootutil_public.c`:

In file included from /Users/todi/bloomlife/zephyr-workspace/bootloader/mcuboot/boot/bootutil/zephyr/../../zephyr/include/sysflash/pm_sysflash.h:13,
                 from /Users/todi/bloomlife/zephyr-workspace/bootloader/mcuboot/boot/bootutil/zephyr/../../zephyr/include/sysflash/sysflash.h:10,
                 from /Users/todi/bloomlife/zephyr-workspace/bootloader/mcuboot/boot/bootutil/src/bootutil_public.c:43:
/Users/todi/bloomlife/zephyr-workspace/bootloader/mcuboot/boot/bootutil/zephyr/../../zephyr/include/mcuboot_config/mcuboot_config.h:75:2: error: #error "CONFIG_BOOT_SWAP_USING_MOVE not set"
   75 | #error "CONFIG_BOOT_SWAP_USING_MOVE not set"
      |  ^~~~~

Or, when I explicitly set CONFIG_BOOT_SWAP_USING_MOVE, an error is issued during the configuration phase of the build, complaining about the unknown BOOT_SWAP_USING_MOVE configuration option:

/Users/todi/bloomlife/zephyr-workspace/lovelace-pod-firmware/prj.conf:82: warning: attempt to assign the value 'y' to the undefined symbol BOOT_SWAP_USING_MOVE
Parsing /Users/todi/bloomlife/zephyr-workspace/zephyr/Kconfig
Loaded configuration '/Users/todi/bloomlife/zephyr-workspace/zephyr/boards/nordic/nrf5340dk/nrf5340dk_nrf5340_cpuapp_defconfig'
Merged configuration '/Users/todi/bloomlife/zephyr-workspace/lovelace-pod-firmware/prj.conf'
Merged configuration '/Users/todi/bloomlife/zephyr-workspace/lovelace-pod-firmware/build/lovelace-pod-firmware/zephyr/.config.sysbuild'

error: Aborting due to Kconfig warnings

CMake Error at /Users/todi/bloomlife/zephyr-workspace/zephyr/cmake/modules/kconfig.cmake:395 (message):
  command failed with return code: 1
Call Stack (most recent call first):
  /Users/todi/bloomlife/zephyr-workspace/nrf/cmake/modules/kconfig.cmake:29 (include)
  /Users/todi/bloomlife/zephyr-workspace/zephyr/cmake/modules/zephyr_default.cmake:132 (include)
  /Users/todi/bloomlife/zephyr-workspace/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
  /Users/todi/bloomlife/zephyr-workspace/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
  CMakeLists.txt:29 (find_package)


-- Configuring incomplete, errors occurred!

This is the relevant part of the prj.config file:

CONFIG_MCUBOOT_BOOTUTIL_LIB=y
CONFIG_BOOT_SWAP_USING_MOVE=y

When I try to instead add `SB_CONFIG_BOOT_SWAP_USING_MOVE=y` to sysbuild.conf, I get the very same error.

/Users/todi/bloomlife/zephyr-workspace/lovelace-pod-firmware/sysbuild.conf:22: warning: attempt to assign the value 'y' to the undefined symbol BOOT_SWAP_USING_MOVE
Parsing /Users/todi/bloomlife/zephyr-workspace/zephyr/share/sysbuild/Kconfig
Loaded configuration '/Users/todi/bloomlife/zephyr-workspace/lovelace-pod-firmware/build/_sysbuild/empty.conf'
Merged configuration '/Users/todi/bloomlife/zephyr-workspace/lovelace-pod-firmware/sysbuild.conf'

error: Aborting due to Kconfig warnings

What do I have to do, to use that library?

best regards and thanks in advance,

Torsten

Nordic SDK version used: v2.7.99-cs2

[Menon]

Hello,

When I try to instead add `SB_CONFIG_BOOT_SWAP_USING_MOVE=y` to sysbuild.conf, I get the very same error.

I believe this method is correct. However, based on the error message you shared, it looks like BOOT_SWAP_USING_MOVE is not recognized in the sysbuild.conf.

Please check the build configuration files to see if the configuration values have been propagated correctly. Make sure to check both the mcuboot build config and the application build config files.

Kind Regards,

Abhijith

[Torsten Robitzki]

Hello Abhijith,

to be honest, I do not understand your answer. I've showed, what I've tried so far and using the configuration above, results in an error message. The configuration in question is even cited and you agree with me, that it should work.

But: It doesn't work. I applied the very same change to an example given to my by one of your colleagues (https://devzone.nordicsemi.com/f/nordic-q-a/115570/using-mcuboot-with-nrf5340 peripheral_lbs_enc_fota.zip) and it results in the very same error message.

If you say, I should check the configuration files: What is the expected configuration?

To me, it looks like, I received an answer from ChatGPT. I apologize, if I'm wrong.

best regards

Torsten

[Menon]

Hello Torsten,

Sorry if my answer was not clear to you. I didn't ask to check your configuration files. I can already see that you are enabling that in your project (which I believe is a correct method), instead I was pointing to the build configuration, i.e. to verify if the configuration you enabled has been properly reflected after the build. Sometimes even if you enabled, this might not get reflected, causing errors. For example if you check the file  build\mcuboot\zephyr-->.config you could see which ever configs get enabled after the build. For the application, check build\zephyr-->.config, see if SB_CONFIG_BOOT_SWAP_USING_MOVE=y is getting enabled in any of the build configs.

I haven't tested this on my end after the introduction of Sysbuild, but I am not sure why you felt the answer was from Chatgpt. I have only asked to verify if configs are getting properly enabled after the build (asked this since the error messages says so). If you are still confused please share the build folder and I can have a look.

Kind Regards,

Abhijith 

[Menon]

Hello Torsten,

I was looking more into this, and I think the config CONFIG_MCUBOOT_BOOTUTIL_LIB cannot be directly enabled. Instead, it is selected by enabling CONFIG_MCUBOOT_IMG_MANAGER. Try enabling this configuration inside the prj.conf and see if it makes any changes.

Kind Regards,

Abhijith

[Torsten Robitzki]

Hi Abhijith,

looks like this is working. At least, this builds and I also expect it to work at runtime.

Thank you very much,

Torsten