https://devzone.nordicsemi.com/f/nordic-q-a/87095/nrf9160-uicr-registersHi! We are trying to make our project more secure following the Nordic documentation, but we absolutely don&#39;t know how to change the values of our registers, furthermore is it possible to change that in the secure domain? For example, we are trying toen-USTelligent Community 13Fri, 22 Apr 2022 13:36:30 GMThttps://devzone.nordicsemi.com/thread/364500?ContentTypeID=1Fri, 22 Apr 2022 13:36:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:48ee5e9f-4b5f-46cb-a15e-a93a021af4f2Jared<p>Hi,</p> <p>You can use nRF Command line tools:</p> <p><pre class="ui-code" data-mode="text">nrfjprog --memwr 0x00FF8000 --val 0 </pre></p> <p>Then you need to do a reset as the CPU reads UICR&nbsp;during start-up.</p> <p>Any subsequent operations with a debugger should then return an error stating readback protection has been enabled.</p> <p>regards</p> <p>Jared</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/363970?ContentTypeID=1Wed, 20 Apr 2022 13:42:47 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7a94c73d-30e4-47ee-adef-d63a685a0d3fGioele<p>Okay byt how can i write to the register to activate it?</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/363968?ContentTypeID=1Wed, 20 Apr 2022 13:39:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:507be8fd-d7de-498e-a8db-523eb16ea8c2Jared<p>Hi,</p> <p>The APPROTECT feature has been described in the <a href="https://infocenter.nordicsemi.com/topic/ps_nrf9160/dif.html">Debug and Trace section</a> in the product specification. You have to use a debugger and write to the <a href="https://infocenter.nordicsemi.com/topic/ps_nrf9160/uicr.html?cp=2_0_0_3_5_0_0#register.APPROTECT">APPROTECT</a>&nbsp;register to activate it.</p> <p>regards</p> <p>Jared&nbsp;</p><div style="clear:both;"></div>