https://devzone.nordicsemi.com/f/nordic-q-a/69188/nrf9160-protected-codeDear Sir. In my program 2 strings I need to protect when a new firmware is updated. #define PROD_DATE &quot;PROD_DATE_03_12-2020&quot; #define IRON_NUMBER &quot;IRON_1234567899999&quot; How can I achieve this goal ?. Please Advise.en-USTelligent Community 13Mon, 07 Dec 2020 13:32:03 GMThttps://devzone.nordicsemi.com/thread/283560?ContentTypeID=1Mon, 07 Dec 2020 13:32:03 GMT137ad170-7792-4731-bb38-c0d22fbe4515:07958d77-256a-4e58-a1de-94f20598d756Einar Thorsrud<p>Hi,</p> <p>The typical location for such information (serial number etc) is in the section of the <a href="https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/uicr.network/doc/uicr.network.html?cp=3_0_0_5_3_1">UICR</a> that are reserved for customer usage. This is a persistent flash register that is typically never modified after production. You may want to skip&nbsp;the prefixes (&quot;PROD_DATE_&quot; and &quot;IRON_&quot;) that I assume is common for all and thus contain no information in order to use less of the UICR for this.</p><div style="clear:both;"></div>