https://devzone.nordicsemi.com/f/nordic-q-a/1219/urgent-a-big-problem-happened-i-can-t-download-and-debugmy application is based on the BLE example: ble_app_hrs. it works well before, but when I add some functions to configure the GPIOTE , and then download to the Device, it doesn&#39;t work . And I can&#39;t download or debug or erase anymore !!! the nrfgo studioen-USTelligent Community 13Wed, 05 Mar 2014 10:19:51 GMThttps://devzone.nordicsemi.com/thread/5636?ContentTypeID=1Wed, 05 Mar 2014 10:19:51 GMT137ad170-7792-4731-bb38-c0d22fbe4515:88c9875c-37c3-44bb-9ed5-68f377f38f9fOle Morten<p>When an nRF51 series device is in system off, the debug interface is not available, and the chip will either have to be woken up (by pressing a wake-up button) or recovered, before being programmed again.</p> <p>For the heart rate example, it can usually be woken up by pressing one of the buttons.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/5635?ContentTypeID=1Fri, 28 Feb 2014 02:25:21 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c25547e9-5cc9-40d4-99ed-e216bc7f5adeJin Lu<p>Thank u, it works again, but when I download my application to it , the same thing happened . could you tell me why this happened ? I just want add some GPIO interruputs to the application to implement button feature.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/5634?ContentTypeID=1Thu, 02 Jan 2014 14:50:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bda88d9b-500d-4061-9b54-c33e6271a347Ole Morten<p>Can you please try to do a recover from the command line? This can be done by running nrfjprog --recover from a cmd prompt. nrfjprog is located in C:\Program Files (x86)\Nordic Semiconductor\nrf51\bin.</p><div style="clear:both;"></div>