Known issue "Partitioning limitation with MCUboot swap move" workaround with direct-xip?

[olof.stacke]

Hi,

We're a bit troubled by the known issue NCSDK-20567: Partitioning limitation with MCUboot swap move, and are trying to find a work around.

Since the issue is with Mcuboots swap space, we were thinking of using DFU mode Direct-XIP, since it doesn't use any swap space.

1. Could this be a viable workaround?

2. We haven't been able to find any good documentation on how to use Direct-XIP. Can anyone point us in the the right direction, or give an explanation on how to do it?

3. Is there any information on when the issue might be solved?

Thank you!

[Vidar Berg]

Hi,

The problem is that the image trailer varies in size depending on your project configurations and the build system will sometimes fail to give you a warning/error if the image header + FW image + image trailer exceeds the size of the mcuboot slot. However, you can catch this issue by testing DFU locally before distributing the update.

The known issue only mentions the swap move algorithm to be affected by this, so I assume using xip or "upgrade only" (SB_CONFIG_MCUBOOT_MODE_OVERWRITE_ONLY=y) should be ok.

 Fixing the "known issue" Partitioning limitation with MCUboot swap move  

Documentation on how to enable xip can be found here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/app_dev/device_guides/nrf52/fota_update.html#build_configuration_additions_for_mcuboot_in_the_direct-xip_mode. Note: this applies to SDK v2.7.0 and later.

Best regards,

Vidar