https://devzone.nordicsemi.com/f/nordic-q-a/78457/add-ble-buttonless-dfu-service-to-custom-applicationHi, in my custom nRF52805 peripheral application, I used Nordic NUS Service to transmit sensor&#39;s data. By using SDK17 example code &lt;ble_app_buttonless_dfu&gt;, I could OTA DFU for only 1 time. I mean, after finish uploading my custom firmware, the DFU buttonen-USTelligent Community 13Wed, 11 Aug 2021 11:59:30 GMThttps://devzone.nordicsemi.com/thread/324462?ContentTypeID=1Wed, 11 Aug 2021 11:59:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6148b2de-f0f3-43e0-a639-332421786c1aEinar Thorsrud<p>Hi,</p> [quote user=""]1) I believe that It&#39;s because when my custom firmware&nbsp;doesn&#39;t include the BLE buttonless DFU service. Is that right?[/quote] <p>Yes, that is correct.</p> [quote user=""]2) Is there any tutorial link to show me how to include the BLE&nbsp;buttonless DFU service in my custom application?&nbsp;[/quote] <p>There are no tutorial sowing specifically how to add Buttonless DFU service. However, you can look at the <a href="https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/ble_sdk_app_buttonless_dfu.html">Buttonless DFU Template Application</a>&nbsp;and copy the relevant parts from there.</p> [quote user=""]3) Should I learn &quot;add new BLE services&quot; first, then learn &quot;add BLE buttonless DFU service&quot;?&nbsp;[/quote] <p>That is up to you. You may also be interested in this generic <a href="https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/merging-two-ble-examples-together">tutorial about merging BLE examples</a>.</p><div style="clear:both;"></div>