Hi,
I am attempting to get the zephyr usb dfu sample located at ncs/zephyr/samples/usb/dfu to work using external flash. I am using the nrf52833 on a custom board in combination with mx25r32 flash chip on ncs version 2.4.0.
Firstly, I have been able to get the dfu working with no issues when I don't configure the project to use external flash. I build the project with the default usb device name, flash it and see that it shows up as a usb device. Then I change the name, rebuild the project and use dfu-util to send app_update.bin to the image 1 slot of the device. I reboot the device, it swaps in the new image and I see my newly named usb device show up. Unfortunately, I need the extra internal flash space as my application is larger than 250 kb.
I then make the following changes to the prj.conf file located at ncs/bootloader/mcuboot/boot/zephyr/prj.conf
CONFIG_MULTITHREADING=y CONFIG_SPI=y CONFIG_SPI_NOR=y CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096 CONFIG_PM_EXTERNAL_FLASH=y CONFIG_PM_EXTERNAL_FLASH_DEV_NAME="MX25R32" CONFIG_PM_EXTERNAL_FLASH_BASE=0 CONFIG_PM_EXTERNAL_FLASH_SIZE=0x73000
I then make the following change to the pm.yml located at the same place
mcuboot_secondary:
region: external_flash
size: CONFIG_PM_EXTERNAL_FLASH_SIZE
I also add the following to the prj.conf file in the usb dfu sample
CONFIG_SPI=y CONFIG_SPI_NOR=y CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096 CONFIG_PM_EXTERNAL_FLASH=y CONFIG_PM_EXTERNAL_FLASH_DEV_NAME="MX25R32" CONFIG_PM_EXTERNAL_FLASH_BASE=0 CONFIG_PM_EXTERNAL_FLASH_SIZE=0x73000
Once I make these changes, everything builds fine and I see the new application size is basically doubled, which to me means that it is in fact configured correctly for storing the secondary image on external flash. I repeat the steps to get a new image on the device just as a I did before and everything seems to work fine. However, when I reboot the device the new usb device is never seen. I see the bootloader try to swap the new image in but it then says that there is no valid firmware image in the primary slot.
I also run into the same issue when I use SMP over BLE. The image is successfully added and the mcumgr image list command even shows that there are two firmware images on the device. But when I reboot, the bootloader tries to swap in the new image but then fails to validate it.
Am I doing something wrong or is this only supposed to work with QSPI?
The external flash works fine on its own as I have the NVS system stored there and I am able to use it without any issues.
