https://devzone.nordicsemi.com/f/nordic-q-a/119517/nrf52840-zigbee-coordniator-router-ble-ota-required-flash-sizeHi Team, Is it feasible to have Zigbee coordinator + router and OTA via Ble in nrf52840? We are struggling to reduce flash size.en-USTelligent Community 13Wed, 05 Mar 2025 15:47:41 GMThttps://devzone.nordicsemi.com/thread/526042?ContentTypeID=1Wed, 05 Mar 2025 15:47:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:9e6d9049-05c6-4a81-b5ec-a6656cfe0688Maria Gilje<p>Hello, </p> [quote user=""]Is it feasible to have Zigbee coordinator + router and OTA via Ble in nrf52840?[/quote] <p>This is feasable to do implement, but you need to enable external flash for MCUboot. Some relevant documentation can be found <a href="https://docs.nordicsemi.com/bundle/ncs-2.9.1/page/nrf/app_dev/bootloaders_dfu/mcuboot_nsib/bootloader_partitioning.html#using_external_flash_memory_partitions">here</a> (nRF Connect SDK v2.9.1). The <a href="https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/">DFU/FOTA Lesson</a> from the nRF Connect SDK Intermediate course can also be helpful, specifically the exercise which covers <a href="https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-9-bootloaders-and-dfu-fota/topic/exercise-3-dfu-with-external-flash/">DFU with external flash</a>. </p> [quote user=""]We are struggling to reduce flash size.[/quote] <p>You can also refer to the Memory footprint optimization page if you haven&#39;t already which can help to reduce the size of your application further. </p> <p>Best regards,</p> <p>Maria</p><div style="clear:both;"></div>