https://devzone.nordicsemi.com/f/nordic-q-a/105820/changing-deviceid-nrf5340Hi there, I use an nRF5340DK with TF_M enabled and NCS 2.4.2. As I understand the DeviceID gets programmed during production of the chip and can&#39;t be changed afterwards. Therefore it should stay the same all the time; however, somehow this isen-USTelligent Community 13Wed, 22 Nov 2023 19:14:18 GMThttps://devzone.nordicsemi.com/thread/457026?ContentTypeID=1Wed, 22 Nov 2023 19:14:18 GMT137ad170-7792-4731-bb38-c0d22fbe4515:50a3fc11-be20-4146-ab04-82bea31fa647SirBuhi<p>Thank you Sigurd, that helped!</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/456535?ContentTypeID=1Mon, 20 Nov 2023 18:25:35 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2f971c48-8820-49d8-82ba-2ea9bd0f7045Sigurd<p>Hi!</p> [quote user=""]I use an nRF5340DK with TF_M enabled and NCS 2.4.2.[/quote] <p>FICR is a <a href="https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/ficr/doc/ficr.html?cp=4_0_0_4_3_1_0#topic">secure peripheral</a>, so if you are trying to access it with TFM enabled, you would need to use&nbsp;secure_read_word(), example usage:&nbsp;<a href="https://github.com/nrfconnect/sdk-nrf/blob/v2.5.0/samples/tfm/tfm_hello_world/src/main.c#L88">https://github.com/nrfconnect/sdk-nrf/blob/v2.5.0/samples/tfm/tfm_hello_world/src/main.c#L88</a></p><div style="clear:both;"></div>