nRF51 not starting after powerup

nRF51 not starting after poweruphttps://devzone.nordicsemi.com/f/nordic-q-a/17868/nrf51-not-starting-after-powerupI have designed several boards for the nRF51822-QFAA, namely with/for the Waveshare Core51822 module. While one is working as expected - namely my "Orchid Lamp" (see links below) - others - namely my "nRFduino" - are only working, when the attacheden-USTelligent Community 13Mon, 21 Nov 2016 19:32:03 GMTRE: nRF51 not starting after poweruphttps://devzone.nordicsemi.com/thread/68881?ContentTypeID=1Mon, 21 Nov 2016 19:32:03 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f6664f5c-1b47-4531-9114-72ef35477a94Matthias<p>Not a hardware problem: nRFduino starts when using other firmwares.</p><div style="clear:both;"></div>