https://devzone.nordicsemi.com/f/nordic-q-a/6884/why-i-can-t-program-my-nrf51-dk-through-keil-download-buttonNow, I&#39;m using &quot;nRF51\peripheral\temperature&quot; example to test something for my nRF51 DK board. I have upgraded sofeDevice s110 v8.0.0 in DK and I can use Keil &quot;Download&quot; button to flash &quot;ble_app_uart&quot; application into it. But when I open &quot;temperatureen-USTelligent Community 13Tue, 05 May 2015 07:45:16 GMThttps://devzone.nordicsemi.com/thread/24258?ContentTypeID=1Tue, 05 May 2015 07:45:16 GMT137ad170-7792-4731-bb38-c0d22fbe4515:35903b52-794a-4880-aba9-cc31c0ff4d1bSusheel Nuguru<p>Seems like you have a softdevice located at the address where you are trying to download your application.</p> <p>go to command prompt and type</p> <blockquote> <p>nrfjprog -e -r</p> </blockquote> <p>Then try to download again.</p><div style="clear:both;"></div>