https://devzone.nordicsemi.com/f/nordic-q-a/71267/unable-to-program-nrf51422-with-sectorerase-flag-forced-chiperase-to-update-fwHello, I am having some problems with what i assume is the readback protection. Is it possible to update the firmware of the device without deleting UIRC (serial number among other things)? Softdevice: nrf51422_xxAA using debug build with readback enableden-USTelligent Community 13Mon, 15 Feb 2021 16:41:00 GMThttps://devzone.nordicsemi.com/thread/294452?ContentTypeID=1Mon, 15 Feb 2021 16:41:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a8599db8-f619-48b3-b4d2-acf209276720Daniel Wang[quote userid="100323" url="~/f/nordic-q-a/71267/unable-to-program-nrf51422-with-sectorerase-flag-forced-chiperase-to-update-fw"]Is it possible to update the firmware of the device without deleting UIRC (serial number among other things)?<br />[/quote] <p>Yes, if readback protection is not enabled.</p> <p>You can check with&nbsp;nrfjprog --memrd 0x10001004 , it returns FFFFFFFF when it&#39;s not enabled</p> <p>If not enabledf, then maybe you have a very old version of nRF51&nbsp;<a href="https://devzone.nordicsemi.com/f/nordic-q-a/11714/flash-external-nrf51422-with-nrf51-dk">https://devzone.nordicsemi.com/f/nordic-q-a/11714/flash-external-nrf51422-with-nrf51-dk</a>&nbsp;, or using old nrfjprog, or maybe have some HW issue with your board.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/292642?ContentTypeID=1Wed, 03 Feb 2021 10:56:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3ea3e2da-8f76-47f4-9bf6-8fa2f7f5d637magnusss<p>edit: Serial number is at 0x10001080, typo</p><div style="clear:both;"></div>