https://devzone.nordicsemi.com/f/nordic-q-a/60816/fota-dfu-from-softdevice-to-zephyrI have some nRF52832 devices that have been flashed with a Softdevice v13 based firmware and can receive OTA firmware updates. Unfortunately their enclosures are sealed and cannot be easily opened to flash the firmware via SWD/JTAG. Is it possible toen-USTelligent Community 13Wed, 29 Apr 2020 13:21:52 GMThttps://devzone.nordicsemi.com/thread/247362?ContentTypeID=1Wed, 29 Apr 2020 13:21:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:db398044-facf-422a-98d7-62c3431a5562Edvin<p>Hello,</p> <p>I am sorry, but it is not possible to DFU from the nRF5 Bootloader to the Zephyr bootloader.</p> <p>The MCUboot bootloader via nRF5 SDK bootloader is a straight no. You&nbsp;<strong>may</strong> be able to update the application to a zephyr application, but you can&#39;t delete the softdevice, because the old bootloader will require it for updates. So you would need a softdevice and the zephyr BLE stack at the same time, so probably not much flash left for the application.</p> <p></p> <p>So unfortunately, the short answer is no. It is probably possible to work together some half-way solution, like I talked about, but it will not be straight forward (and we are not planning to do it), and you will not be able to use the MCUboot. If you want to use a Zephyr bootloader, you need to use a programmer.</p><div style="clear:both;"></div>