Building nrf7002/nrf5340 application with wifi firmware in external flash (STORE)

[BrianW]

As I am running out of flash space on the nrf5340 (mainly due to the 500+kB needed to run a basic wifi application), I want to put the nrf70 firmware into the external flash (connected via QSPI on my custom PCB).

The simplest way looked to be using the CONFIG_NRF_WIFI_PATCHES_EXT_FLASH_STORE option (even though my hw would support the XIP case). I also want to give the DFU option using mcuboot.

I set up my partitions as per the doc:

# allow wifi patches to be updated by mcuboot

nrf70_wifi_fw_mcuboot_pad:

    region: external_flash

    address: 0x741e00

    size: 0x200

    #device: MX25R64

nrf70_wifi_fw:

    region: external_flash

    # 128kB size, its for the wifi fw

    address: 0x742000

    size: 0x20000

mcuboot_primary_2:

    region: external_flash

    orig_span: &id003

    - nrf70_wifi_fw_mcuboot_pad

    - nrf70_wifi_fw

    span: *id003

    address: 0x741e00

    size: 0x20200

    #device: MX25R64

mcuboot_secondary_2:

    region: external_flash

#    address: 0x762e00

    address: 0x762000

    size: 0x20200

    #device: MX25R64

I enable the options in prj.conf as per what I understand from the doc and the source:

CONFIG_NRF_WIFI_PATCHES_BUILTIN=n

CONFIG_NRF_WIFI_PATCHES_EXT_FLASH_STORE=y

CONFIG_NRF_WIFI_FW_PATCH_INTEGRITY_CHECK=n

CONFIG_NRF_WIFI_FW_PATCH_DFU=y

The partitions work fine, the partition ids are in pm_config.h as expected by the ext_fw_load.c code.

However, the build fails as a rule to generate the hex file required (nrf70.hex) from the binary blob (nrf70.bin) doesn't seem to be in the mix:

-- Configuring done
-- Generating done
-- Build files have been written to: C:/work/dev/if-device-nrf53/cc1-med/build
←[92m-- west build: building application
←[0mninja: error: 'zephyr/nrf70.hex', needed by 'zephyr/nrf70_signed.hex', missing and no known rule to make it
FATAL ERROR: command exited with status 1: 'C:\ncs\toolchains\b620d30767\opt\bin\cmake.EXE' --build 'C:\work\dev\if-device-nrf53\cc1-med\build'

The bin blob, nrf70.bin, should be nrfxlib/nrf_wifi/bin/ncs/default/nrf70.bin for my case, as I have 

CONFIG_NRF70_SYSTEM_MODE=y

What config is missing to force the hex generation?

[BrianW]

BrianW said:

What config is missing to force the hex generation?

The answer of course is that the generation of the .hex from the .bin is only done when building using sysbuild, not multi-image. (in NCS 2.8 and NCS 2.9).

So, to enable placing the wifi firmware in external flash (store or xip) requires you to build with sysbuild.... 

Note : this is not documented anywhere I can find, and particularly is not explicitly mentioned in the pages about using external storage

https://docs.nordicsemi.com/bundle/ncs-2.8.0/page/nrf/app_dev/device_guides/nrf70/fw_patches_ext_flash.html