simultaneous DFU on nRF5340 and NCS 2.6.1 without external flash

[Mary]

NCS 2.6.1
nRF5340

My project is based on coap_client, and I am trying to get DFU to work on an off-the-shelf dongle, which has no external flash.  I have looked at this ticket:

 how to implement simultaneous dfu on 5340 ncs2.4 without external flash 

I am aware of the flash limitations, but have managed to get it to fit.

pm_static.yml

app:
  address: 0x10200
  end_address: 0x76000
  region: flash_primary
  size: 0x65e00
mcuboot:
  address: 0x0
  end_address: 0x10000
  placement:
    before:
    - mcuboot_primary
  region: flash_primary
  size: 0x10000
mcuboot_pad:
  address: 0x10000
  end_address: 0x10200
  placement:
    before:
    - mcuboot_primary_app
  region: flash_primary
  size: 0x200
mcuboot_primary:
  address: 0x10000
  end_address: 0x76000
  orig_span: &id001
  - mcuboot_pad
  - app
  region: flash_primary
  sharers: 0x1
  size: 0x66000
  span: *id001
mcuboot_primary_app:
  address: 0x10200
  end_address: 0x76000
  orig_span: &id002
  - app
  region: flash_primary
  size: 0x65e00
  span: *id002
mcuboot_secondary:
  address: 0x76000
  end_address: 0xdc000
  placement:
    after:
    - mcuboot_primary
    align:
      start: 0x1000
  region: flash_primary
  share_size:
  - mcuboot_primary
  size: 0x66000

mcuboot_primary_1:
  address: 0x0
  size: 0x20000
  device: flash_ctrl
  region: ram_flash
ram_flash_empty:
  address: 0x20000
  size: 0x5a000
  device: flash_ctrl
  region: ram_flash  
mcuboot_secondary_1:
  address: 0xdc000
  end_address: 0xfc000
  placement:
    align:
      start: 0x1000
  region: flash_primary
  size: 0x20000

otp:
  address: 0xff8100
  end_address: 0xff83fc
  region: otp
  size: 0x2fc
pcd_sram:
  address: 0x20000000
  end_address: 0x20002000
  placement:
    after:
    - start
  region: sram_primary
  size: 0x2000
ram_flash:
  address: 0x40000
  end_address: 0x40000
  region: ram_flash
  size: 0x0
rpmsg_nrf53_sram:
  address: 0x20070000
  end_address: 0x20080000
  placement:
    before:
    - end
  region: sram_primary
  size: 0x10000

settings_storage:
  address: 0xfc000
  end_address: 0x100000
  placement:
    align:
      start: 0x1000
    before:
    - end
  region: flash_primary
  size: 0x4000

sram_primary:
  address: 0x20002000
  end_address: 0x20070000
  region: sram_primary
  size: 0x6e000

I copied board files from the 5340DK modified them as necessary for the hardware.  I have included a node for the phantom flash controller in then rf5340_common_cpuapp.dts file.

mcuboot/prj.conf

##########################################
### Configure required bootloader settings
##########################################
CONFIG_MULTITHREADING=y
CONFIG_BOOT_MAX_IMG_SECTORS=256

# From: https://github.com/simon-iversen/sdk-zephyr/blob/serial_dfu_ext_flash_hello_world/samples/hello_world/child_image/mcuboot/prj.conf

# In order to provide board specific configurations to the MCUboot child image
# we also need to provide a base configuration for MCUboot. This file contains
# the basic configurations needed to successfully build and run MCUboot.

# MCUboot requires a large stack size, otherwise an MPU fault will occur
CONFIG_MAIN_STACK_SIZE=10240

CONFIG_DEBUG_OPTIMIZATIONS=y
CONFIG_SIZE_OPTIMIZATIONS=y
 
# Enable flash operations
CONFIG_FLASH=y

# This must be increased to accommodate the bigger images.
CONFIG_BOOT_MAX_IMG_SECTORS=256

CONFIG_LOG=y
CONFIG_LOG_MODE_MINIMAL=y # former CONFIG_MODE_MINIMAL
### Ensure Zephyr logging changes don't use more resources
CONFIG_LOG_DEFAULT_LEVEL=3
### Decrease footprint by ~4 KB in comparison to CBPRINTF_COMPLETE=y
CONFIG_CBPRINTF_NANO=y


# Must match the board yaml file: pm_static_nrf5340.yml
CONFIG_PM_PARTITION_SIZE_MCUBOOT=0x10000
CONFIG_PM_PARTITION_SIZE_MCUBOOT_SCRATCH=0x10000

CONFIG_MCUBOOT_INDICATION_LED=y

CONFIG_PINCTRL=y

CONFIG_BOOT_WATCHDOG_FEED=y

# Public key, ECDSA
CONFIG_BOOT_SIGNATURE_KEY_FILE="d:/myproject/child_image/mcuboot/myproject_priv.pem"
CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256=y

# Simultaneous updates (cpuapp, cpunet)
# See:  https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/app_dev/device_guides/nrf53/simultaneous_multi_image_dfu_nrf5340.html
# Enable flash simulator
#CONFIG_FPROTECT=y
CONFIG_PCD_APP=y
# The network core cannot access external flash directly. The flash simulator must be used to
# provide a memory region that is used to forward the new firmware to the network core.
CONFIG_FLASH_SIMULATOR=y
CONFIG_FLASH_SIMULATOR_DOUBLE_WRITES=y
CONFIG_FLASH_SIMULATOR_STATS=n

CONFIG_NRF53_MULTI_IMAGE_UPDATE=y
CONFIG_UPDATEABLE_IMAGE_NUMBER=2

CONFIG_BOOT_UPGRADE_ONLY=y
CONFIG_BOOT_IMAGE_ACCESS_HOOK_NRF5340=y
CONFIG_BOOT_IMAGE_ACCESS_HOOKS=y

overlay-dfu_support.conf

#
# Copyright (c) 2021 Nordic Semiconductor
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#

# Enable MCUboot bootloader
CONFIG_BOOTLOADER_MCUBOOT=y
CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=y

# MCU Manager and SMP configuration
CONFIG_ZCBOR=y
CONFIG_MCUMGR=y
#CONFIG_MCUMGR_CMD_IMG_MGMT=y
#CONFIG_MCUMGR_CMD_OS_MGMT=y
#CONFIG_MCUMGR_SMP_BT=y
#CONFIG_MCUMGR_SMP_BT_AUTHEN=n
#CONFIG_MCUMGR_BUF_COUNT=6

# Increase BT MTU and RX buffer for big size DFU messages
#CONFIG_BT_L2CAP_TX_MTU=260
#CONFIG_BT_BUF_ACL_RX_SIZE=264

# Reduce GAP event length to avoid heavy BLE traffic generated during DFU
#CONFIG_BT_CTLR_SDC_MAX_CONN_EVENT_LEN_DEFAULT=3000

# Enable minimal logging implementation to decrease memory footprint
#CONFIG_LOG_MODE_MINIMAL=y

# Added to match DTS
CONFIG_PM_PARTITION_SIZE_SETTINGS_STORAGE=0x4000
CONFIG_SETTINGS_NVS_SECTOR_COUNT=4

# NCS2 additions
# Image manager
CONFIG_IMG_MANAGER=y
CONFIG_FLASH=y
CONFIG_FLASH_MAP=y
CONFIG_STREAM_FLASH=y
CONFIG_IMG_ERASE_PROGRESSIVELY=y
#CONFIG_MCUMGR_GRP_IMG=y
#CONFIG_MCUMGR_GRP_OS=y
# Enable statistics and statistic names.
#CONFIG_STATS=y
#CONFIG_STATS_NAMES=y
#CONFIG_MCUMGR_GRP_STAT=y

# DFU Target
#CONFIG_DFU_TARGET=y

CONFIG_IEEE802154_NRF5_RX_STACK_SIZE=1000

# nRF5340
CONFIG_UPDATEABLE_IMAGE_NUMBER=2

The project compiles, and the images seem to be loaded in the correct areas of flash.

D:\myproject\bld_usb40n\zephyr>nrfjprog --verify app_signed.hex
[ #################### ] 2.789s | Verify file - Done verifying

However, the bootloader fails to find a bootable image, and halts here, with fig_rc = -1:

I note that in build\mcuboot\zephyr\.config, 

CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=y

Is the bootloader looking for bootable images in external flash?

If I set CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY=n  in overlay-dfu_support,  mcuboot won't compile, and reports this error:

 error: 'PM_MCUBOOT_PRIMARY_1_ID' undeclared

How can I get this to work?

Mary

[Vidar Berg]

Hello Mary,

Unfortunately, the current implementation assumes that external flash will always be used for multi-image DFU, since there otherwise will be little room left for the application. That said, it looks like it should be possible to support this if you cherry pick the following commits:

- https://github.com/nrfconnect/sdk-nrf/pull/10060 

- https://github.com/nrfconnect/sdk-mcuboot/pull/235 

Best regards,

Vidar

[Mary]

My hardware has a USB port.  Is it possible to use mcumgr or nrfutils to do an update via the UART over USB?

Or is there still a problem with flash space?

Mary

[Vidar Berg]

Flash space is not necessarily a problem, it depends on the size of your current application. For instance, having both slots in internal flash will not work if you are developing a Matter application. 

It is also possible to perform serial recover (DFU within the bootloader) over UART or USB using the mcumgr. There are some un-official samples of this here: https://github.com/hellesvik-nordic/samples_for_nrf_connect_sdk/tree/main/bootloader_samples/serial_recovery 

Vidar