https://devzone.nordicsemi.com/f/nordic-q-a/34693/secure-ble-dfu-bootloader-doubtHi, I have used examples\dfu\secure_bootloader\pca10056_ble application and successfully updated two applications(heart rate and health thermometer) over BLE. In order to do that upon testing first application , for updating second application I wasen-USTelligent Community 13Thu, 24 May 2018 12:09:02 GMThttps://devzone.nordicsemi.com/thread/133230?ContentTypeID=1Thu, 24 May 2018 12:09:02 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3f887d2d-531e-4837-ac13-c72d1741de14Hung Bui<p>Hi Sridhar,&nbsp;</p> <p>&nbsp;</p> <p>If you don&#39;t have a button to enter DFU, you would need to use buttonless solution. Have a look at Appendix 2 on <a href="https://devzone.nordicsemi.com/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader">this guide.&nbsp;</a></p><div style="clear:both;"></div>