https://devzone.nordicsemi.com/f/nordic-q-a/35642/device-firmware-update-over-bleHello, I work on project for BLE communication in DFU mode. I am testing according to the mode defined on the Nordic web page link I did the tests with the BleuZ and with an android application nRF. I start with enable CCCD, then I write the en-USTelligent Community 13Tue, 26 Jun 2018 08:54:48 GMThttps://devzone.nordicsemi.com/thread/137622?ContentTypeID=1Tue, 26 Jun 2018 08:54:48 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7de10c15-014f-4a97-abbf-cff5b6e9835dBj&#248;rn Kvaale<p>May I ask why you are using sdk 11 with the nrf52 dev kit? If I may suggest, I would recommend taking a look at <a href="https://devzone.nordicsemi.com/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader">this great blog post</a> written by an application engineer here at Nordic. It explains the DFU process step by step. In addition, you can use the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.0.0/ble_sdk_app_dfu_bootloader.html?cp=4_0_0_4_3_0">BLE Secure DFU Bootloader exampl</a>e in our latest sdk 15.</p><div style="clear:both;"></div>