https://devzone.nordicsemi.com/f/nordic-q-a/42708/gatt-error-doing-buttonless-dfuHELLO I have trouble connecting dfutarg i am doing this in doing this tutorial I skipped 5,6,7 in step1 and i coudn&#39;t do 5,6,7 in step3 because of not connection here is nrfconnect log i searched this problem and tried tofix but i can&#39;t solveen-USTelligent Community 13Fri, 18 Jan 2019 13:27:42 GMThttps://devzone.nordicsemi.com/thread/166484?ContentTypeID=1Fri, 18 Jan 2019 13:27:42 GMT137ad170-7792-4731-bb38-c0d22fbe4515:cbb571e8-d164-44e1-be5e-23129dbf28bdHung Bui<p>Hi James,&nbsp;</p> <p></p> <p>I would suggest to try testing with the bootloader first before testing with the buttonless.</p> <p>Could you try to follow my guide <a href="https://devzone.nordicsemi.com/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader">here </a>and let me know if it works ?&nbsp;</p> <p>GATT 133 has been an issue with Android for a long time. But we haven&#39;t seen this issue on recent phones . Please make sure you delete bonding on the phone and try turn off and on Bluetooth before testing.&nbsp;</p> <p>You can try capturing a<a href="https://www.nordicsemi.com/eng/Products/Bluetooth-Smart-Bluetooth-low-energy/nRF-Sniffer/"> sniffer trace</a>&nbsp; if you have a nRF52 DK , please follow the documentation of the sniffer.&nbsp;</p><div style="clear:both;"></div>