https://devzone.nordicsemi.com/f/nordic-q-a/37309/mesh-dfu-over-ble-by-using-nrf52840-dk-boardsHi Nordic team, I have 2 nRF52840 DK boards. I followed the steps mentioned in the below link, I am able to Transfer the DFU archive over serial with nrfutil(LED keeps blinking on the DFU performed board). http://infocenter.nordicsemi.com/indexen-USTelligent Community 13Sun, 12 Aug 2018 20:19:02 GMThttps://devzone.nordicsemi.com/thread/143824?ContentTypeID=1Sun, 12 Aug 2018 20:19:02 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3f63138e-804b-449d-893c-5ec50e9081e3bjorn-spockeli<p>Hi Prasanna,&nbsp;</p> <p>Q1: The serial bootloader will automatically start transferring firmware image to the other mesh nodes over BLE after it has received the firmware image over the serial interface. This is stated in the <a title="DFU quick start guide" href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.meshsdk.v2.1.1/md_doc_getting_started_dfu_quick_start.html?cp=4_1_0_3_2">DFU quick start guide</a>.&nbsp;&nbsp;</p> <p>Q2: The mesh node will print&nbsp;DFU END! in the log output when DFU has finished.</p> <p>Q3: The Bluetooth Mesh is a flooding mesh, i.e. no connections are made.&nbsp; The mesh nodes listen for incoming advertisement packets and then forward these to the other nodes within range. If a mesh node is outside the range of the other mesh nodes when DFU is performed and then joins the mesh at a later point, then it will automatically detect that its firmware version is outdated and will request the mesh to resend the new firmware.&nbsp;&nbsp;</p> <p>Best regards</p> <p>Bjørn&nbsp;</p><div style="clear:both;"></div>