https://devzone.nordicsemi.com/f/nordic-q-a/20229/nrf51-dk---do-not-respondepc cannot recognize nrf51 DK board. what I have done. erase all - not work (log.log attached) power on with reset button. and copy J-Link OB-SAM3U128-V2-NordicSemi 160914.bin fileen-USTelligent Community 13Tue, 07 Mar 2017 07:59:43 GMThttps://devzone.nordicsemi.com/thread/78815?ContentTypeID=1Tue, 07 Mar 2017 07:59:43 GMT137ad170-7792-4731-bb38-c0d22fbe4515:91d81691-b04b-4c98-8838-5f800dc4af30J&#248;rgen Holmefjord<p>Could you upload the log file? Which version of nrfjprog are you using? (you can check this using the command <code>nrfjprog --verison</code>)</p><div style="clear:both;"></div>