USB DFU Sample Application

Overview

This sample app demonstrates use of a USB DFU Class driver provided by the Zephyr project.

Requirements

This project requires an USB device driver. Currently, the USB DFU class provided by the Zephyr project depends on DFU image manager and partition layout. Refer to Flash Partitions for details about partition layout. You SoC must run MCUboot as the stage 1 bootloader. This sample is built as an application for the MCUboot bootloader.

Building and Testing

Building and signing the application

This sample can be built in the usual way (see Building an Application for more details) and flashed with regular flash tools, but will need to be loaded at the offset of SLOT-0.

Application images (such as this sample) must be signed. Use the scripts/imagetool.py script from the MCUboot GitHub repo to sign the image. (See the Using MCUboot with Zephyr documentation for details.)

~/src/mcuboot/scripts/imgtool.py sign \
        --key ~/src/mcuboot/root-rsa-2048.pem \
        --header-size 0x200 \
        --align 8 \
        --version 1.2 \
        --slot-size 0x60000 \
        ./zephyr/zephyr.bin \
        signed-zephyr.bin

Build and flash MCUboot bootloader for Zephyr project as it is described in the Using MCUboot with Zephyr documentation. Then build, sign and flash the USB DFU sample at the offset of SLOT-0.

Build and sign a second application image e.g. Hello World, which will be used as an image for the update. Do not forget to enable the required MCUboot Kconfig option (as described in MCUboot) by adding the following line to samples/hello_world/prj.conf:

CONFIG_BOOTLOADER_MCUBOOT=y

Testing

The Linux dfu-util tool can be used to backup or update the application image.

Use the following command to backup the SLOT-0 image:

dfu-util --alt 0 --upload slot0_backup.bin

Use the following command to update the application:

dfu-util --alt 1 --download signed-hello.bin

Reset the SoC. MCUboot boot will swap the images and boot the new application, showing this output to the console:

***** Booting Zephyr OS v1.1.0-65-g4ec7f76 *****
[MCUBOOT] [INF] main: Starting bootloader
[MCUBOOT] [INF] boot_status_source: Image 0: magic=unset, copy_done=0xff, image_ok=0xff
[MCUBOOT] [INF] boot_status_source: Scratch: magic=unset, copy_done=0xe, image_ok=0xff
[MCUBOOT] [INF] boot_status_source: Boot source: slot 0
[MCUBOOT] [INF] boot_swap_type: Swap type: test
[MCUBOOT] [INF] main: Bootloader chainload address offset: 0x20000
[MCUBOOT] [INF] main: Jumping to the first image slot0
***** Booting Zephyr OS v1.11.0-830-g9df01813c4 *****
Hello World! arm

Reset the SoC again and MCUboot should revert the images and boot USB DFU sample, showing this output to the console:

***** Booting Zephyr OS v1.1.0-65-g4ec7f76 *****
[MCUBOOT] [INF] main: Starting bootloader
[MCUBOOT] [INF] boot_status_source: Image 0: magic=good, copy_done=0x1, image_ok=0xff
[MCUBOOT] [INF] boot_status_source: Scratch: magic=unset, copy_done=0xe, image_ok=0xff
[MCUBOOT] [INF] boot_status_source: Boot source: none
[MCUBOOT] [INF] boot_swap_type: Swap type: revert
[MCUBOOT] [INF] main: Bootloader chainload address offset: 0x20000
***** Booting Zephyr OS v1.11.0-830-g9df01813c4 *****