https://devzone.nordicsemi.com/f/nordic-q-a/11785/pca10001-board-serialnumber-failed-after-segger-j-link-5-1-updateHello, I use the Segger J-link software with my PCA10001 and recently updated it to last version (v.5.1). After install it asked me to update the firmware to the last version, after updating, the SN field became &quot;-1&quot;. And of course J-Flash popup licenceen-USTelligent Community 13Mon, 08 Feb 2016 23:45:36 GMThttps://devzone.nordicsemi.com/thread/44555?ContentTypeID=1Mon, 08 Feb 2016 23:45:36 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a4083d27-83d6-4e96-a676-49fc9863de3aRK<p>Make sure you have the real latest version of JLink, there&#39;s a note about fixing a serial number bug. If that doesn&#39;t help, I suggest the Segger support forums as only they may be able to help you.</p><div style="clear:both;"></div>