https://devzone.nordicsemi.com/f/nordic-q-a/96308/nrf52840-with-device-protectionHello, Currently we use nRF52840 in some of our products. These devices are programmed with a project inspired by nRF5_SDK_for_Thread_and_Zigbee_v4.1.0 I will have to order BT840-P (nRF52840 with AP Protect security feature). My questions are: en-USTelligent Community 13Fri, 03 Feb 2023 14:43:35 GMThttps://devzone.nordicsemi.com/thread/408041?ContentTypeID=1Fri, 03 Feb 2023 14:43:35 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ea86a099-26e0-4743-8c13-f2e187bee5afEinar Thorsrud<p>Hi,</p> [quote user=""]- If I program these BT840-P with my current project, do I risk having a problem?[/quote] <p>nRF5_SDK_for_Thread_and_Zigbee_v4.1.0 comes with an older MDK that does not support revision 3 of nRF52840, which is the revision with the improved access port protection feature. Therefore, the old firmware must be re-built with a newer <a href="https://www.nordicsemi.com/Products/Development-tools/nRF-MDK">MDK</a> (at least version&nbsp;8.40.2, but I would recommend you pick the latest version). See <a href="https://infocenter.nordicsemi.com/pdf/in_141_v1.1.pdf?cp=19_21">IN141</a> for details.</p> [quote user=""]- My devices also have the Nordic bootloader so that we can update the devices with UART:&nbsp;will using a BT840-P impact the UART update?[/quote] <p>None of the errata workarounds will be enabled in the bootloader unless you re-build it with an updated MDK, so this is the same as for the application. I would not expect that this would cause breaking issues with the bootloader, but it would make change to also rebuild the bootloader with&nbsp;an updated MDK, just as you should with the application.</p><div style="clear:both;"></div>