https://devzone.nordicsemi.com/f/nordic-q-a/89243/inquire-about-downloading-firmware-using-a-usb-cableHello, I am developing a product using nRF52840. I use the DK board to debug and download. However, I would like to implement a firmware update function using USB on my custom board. In other words, I want to download the firmware using a USB cableen-USTelligent Community 13Thu, 23 Jun 2022 11:52:58 GMThttps://devzone.nordicsemi.com/thread/373928?ContentTypeID=1Thu, 23 Jun 2022 11:52:58 GMT137ad170-7792-4731-bb38-c0d22fbe4515:19f3ff76-feb1-4bf4-b491-acf19a2f5b94Einar Thorsrud<p>Hi,</p> <p>It seems like you are describing DFU over USB. That is supported both with the old nRF5 SDK and the new nRF Connect SDK. For the latter, you can look at the <a href="https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.0.0/zephyr/samples/subsys/mgmt/mcumgr/smp_svr/README.html">SMP Server Sample</a>&nbsp;and see the description for USB CDC_ACM (you may also find <a href="https://devzone.nordicsemi.com/guides/nrf-connect-sdk-guides/b/software/posts/ncs-dfu">this tutorial</a> useful, though it does not focus specifically on USB).</p><div style="clear:both;"></div>