RE: Question about simulltaneous multi-image DFU over BLE on nRF5340

Bogdan Marinescu — Mon, 31 Jul 2023 20:00:51 GMT

Apologies, it appears that I misunderstood how CONFIG_BOOT_UPGRADE_ONLY works. This ticket is invalid, so it can be closed.

RE: Question about simulltaneous multi-image DFU over BLE on nRF5340

Bogdan Marinescu — Mon, 31 Jul 2023 13:41:29 GMT

Some clarification about why I find this confusing: the linked that I posted above (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/device_guides/working_with_nrf/nrf53/nrf5340.html#simultaneous-multi-image-dfu) states:

To enable the simultaneous update of multiple images in the MCUboot, set the following options:

CONFIG_BOOT_UPGRADE_ONLY - The simultaneous update of multiple images does not support network core image reversion, so you need to disable application image reversion.

However,CONFIG_BOOT_UPGRADE_ONLY has this effect:

config BOOT_UPGRADE_ONLY
bool "Overwrite image updates instead of swapping"
help
If y, overwrite the primary slot with the upgrade image instead
of swapping them. This prevents the fallback recovery, but
uses a much simpler code path.

So, if CONFIG_BOOT_UPGRADE_ONLY is active, the new firmware image must be written to its primary slot, not its secondary slot, which means that I couldn't possibly do a BLE update from an application that runs on the app core, since that'd effectively overwrite the firmware image on the app core where the application is currently running. I'm probably missing something, but I don't know what.