https://devzone.nordicsemi.com/f/nordic-q-a/1831/can-i-write-an-available-uicr-register-directly-with-nrfjprog-exeI want to use a UICR for device serial number. Correct me if I am wrong but it is my understanding that a UICR cannot be changed programmatically like onboard flash can. So right now I can use the free version of MDK to compile the example code to puten-USTelligent Community 13Sun, 09 Mar 2014 21:56:36 GMThttps://devzone.nordicsemi.com/thread/7926?ContentTypeID=1Sun, 09 Mar 2014 21:56:36 GMT137ad170-7792-4731-bb38-c0d22fbe4515:cf281010-e81a-4b6d-8841-fbed2a785be9David Smoot<p>Nevermind, should have tried &quot;nrfjprog -h&quot; first before I posted the question. Almost everything is spelled out there. For the 51422, if you have the soft device programmed then you can&#39;t erase the UICR without either reprogramming the soft device or erasing all. Once the UICR is erased, you can write what you want to the unused registers with <code>nrfjprog --memwr Address --val value</code></p><div style="clear:both;"></div>