NCS 2.5.1 sample application with MCUBoot updates from external flash

[Shen2]

Is there a sample application that shows how to get a hello world application going with the mcuboot able to do updates from extermal flash?

I am looking at the app with mcu boot sample, building for the nrf52840dk board, but don't understand what needs to be done to configure the mcuboot to work.

I can't find the docuemntation that shows how to actually set up a concrete example,

I have updated prj.conf with

'``

CONFIG_BOOTLOADER_MCUBOOT=y

```

and the sysbuild/mcuboot.conf with

```

CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=y

CONFIG_PM_EXTERNAL_FLASH_BASE=0x0

```

and am seeing the following error

```
In file included from E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/sysflash.h:10,
from E:/ncs/v2.5.1/bootloader/mcuboot/boot/bootutil/src/bootutil_priv.h:33,
from E:/ncs/v2.5.1/bootloader/mcuboot/boot/bootutil/src/swap_scratch.c:25:
E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h: In function '__flash_area_ids_for_slot':
E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:47:60: error: 'PM_MCUBOOT_SECONDARY_ID' undeclared (first use in this function); did you mean 'PM_MCUBOOT_PRIMARY_ID'?
47 | #define FLASH_AREA_IMAGE_0_SLOTS PM_MCUBOOT_PRIMARY_ID, PM_MCUBOOT_SECONDARY_ID
| ^~~~~~~~~~~~~~~~~~~~~~~
E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:52:29: note: in expansion of macro 'FLASH_AREA_IMAGE_0_SLOTS'
52 | #define ALL_AVAILABLE_SLOTS FLASH_AREA_IMAGE_0_SLOTS
| ^~~~~~~~~~~~~~~~~~~~~~~~
E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:67:9: note: in expansion of macro 'ALL_AVAILABLE_SLOTS'
67 | ALL_AVAILABLE_SLOTS
| ^~~~~~~~~~~~~~~~~~~
E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:47:60: note: each undeclared identifier is reported only once for each function it appears in
47 | #define FLASH_AREA_IMAGE_0_SLOTS PM_MCUBOOT_PRIMARY_ID, PM_MCUBOOT_SECONDARY_ID
| ^~~~~~~~~~~~~~~~~~~~~~~
E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:52:29: note: in expansion of macro 'FLASH_AREA_IMAGE_0_SLOTS'
52 | #define ALL_AVAILABLE_SLOTS FLASH_AREA_IMAGE_0_SLOTS
| ^~~~~~~~~~~~~~~~~~~~~~~~
E:/ncs/v2.5.1/bootloader/mcuboot/boot/zephyr/include/sysflash/pm_sysflash.h:67:9: note: in expansion of macro 'ALL_AVAILABLE_SLOTS'
67 | ALL_AVAILABLE_SLOTS
| ^~~~~~~~~~~~~~~~~~~
```

[Vidar Berg]

Hello,

The main step to enabling the bootloader to use the external flash is to create a device tree overlay with the nordic,pm-ext-flash property as shown below.

/ {
	chosen {
		nordic,pm-ext-flash = &mx25r64;
	};
};

Relevant documentation links:

- https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.5.2/nrf/scripts/partition_manager/partition_manager.html#pm-external-flash 

- https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.5.2/nrf/config_and_build/bootloaders_and_dfu/bootloader_external_flash.html#using-external-flash-memory-partitions 

- https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.5.2/nrf/device_guides/working_with_nrf/nrf52/developing.html#fota-updates

Do you want to support over the air updates with BLE, or serial over USB/UART? 

Best regards,

Vidar

[Shen2]

Thanks for that, it has gotten me to the next step, although now I am building but attempting to flash & debug the bootloader and firmware results in a FIH_PANIC in the bootloader as it fails to find a valid application to boot into

and Yes, BLE updates and serial would be good as backups in case the update from external flash fails somehow and the single application slot is left corrupted

[Vidar Berg]

I've put together a demo sample based on 'hello world' which supports the following:

- Serial recover mode in bootlodader. This allows you to perform DFU trough the USB interface. You can press button 0 ('mcuboot-button0') on startup to make the bootloader this mode.

- FOTA over BLE via the application. 

- VERSION file in the project root directory to define the version number for the app image. https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.5.2/zephyr/build/version/index.html 

- Added the 'child_image' folder to apply configuration changes to the mcuboot build. https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.5.2/nrf/config_and_build/multi_image.html#permanent-configuration-changes-to-child-images 

Demo sample

8475.hello_world_dfu.zip

Testing the sample

Build and flash the project onto your board. Next, update the version number in the VERSION file and rebuild the application to create an update image. I also recommend connecting a serial emulator to the Segger VCOM to monitor the DFU process.

Serial recovery:

1. Connect you PC to the nRF USB port on the side of the DK.

2. Press the reset button while keeping button 1 on the DK pressed. Then confirm from the Debug log that the bootloader enters serial recovery mode.

3. Initiate serial DFU. For example, with the 'mcumgr' tool: 

$ mcumgr --conntype serial --connstring "COMx,baud=115200,mtu=4096" image upload build/zephyr/app_update.bin 
# Perform reset to activate and boot new FW image
$ mcumgr --conntype serial --connstring "COMx,baud=115200,mtu=4096" reset

FOTA over BLE:

1. Connect to the device using the Device Manager app on Android or iOS. The device name is 'Zephyr'

2. Upload the app_update.bin from your build directory.

Confirm from that the debug log that the app is printing the new version number after the update is complete.