https://devzone.nordicsemi.com/f/nordic-q-a/8011/what-are-these-magic-registers-4001e504-and-4001e50c-used-to-erase-nrf51422While reading about setting up nRF51 development environment on OS X , I came across the following: Unfortunately the only way to erase the memory is to do some magic register writes: JLinkExe J-Link&gt;w4 4001e504 2 J-Link&gt;w4 4001e50c 1en-USTelligent Community 13Sun, 05 Jul 2015 12:58:35 GMThttps://devzone.nordicsemi.com/thread/28697?ContentTypeID=1Sun, 05 Jul 2015 12:58:35 GMT137ad170-7792-4731-bb38-c0d22fbe4515:41fcf5c6-0cbb-44ac-bd36-48b8909ae370Mahesh Venkitachalam<p>I&#39;ll definitely be doing that from now on!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/28696?ContentTypeID=1Sun, 05 Jul 2015 12:51:15 GMT137ad170-7792-4731-bb38-c0d22fbe4515:57241e73-210c-48b0-b5b8-c50df946d1d8RK<p>I&#39;ve learned through cold bitter experience to search for the last 4 digits or the first 4 digits as it&#39;s usually an offset (last 4) to a base (1st four).</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/28695?ContentTypeID=1Sun, 05 Jul 2015 12:11:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:477fe0ac-578a-47f8-8d55-0c90ab93872cMahesh Venkitachalam<p>I did search in the PDF for these numbers, but I guess I was off by a few bits. Thanks.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/28694?ContentTypeID=1Sun, 05 Jul 2015 05:41:50 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f94afeaa-8d38-4375-bbaa-75cb70db7485RK<p>nrf51 reference manual V2.1 page 15 table 5 plus table 3 on page 13 showing peripheral 30, the NVMC, has base address of 0x4001E000.</p> <p>All documented, no magic.</p><div style="clear:both;"></div>