https://devzone.nordicsemi.com/f/nordic-q-a/57210/programming-nrf52832-always-sets-readbackI’ve been developing the FW for an nRF52832-based module that controls a simple lighting product. The capabilities include support for secure DFU and a modified version of the Nordic BLE UART example for communicating with and configuring the lighten-USTelligent Community 13Fri, 31 Jan 2020 15:56:34 GMThttps://devzone.nordicsemi.com/thread/232133?ContentTypeID=1Fri, 31 Jan 2020 15:56:34 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ca96871c-c79b-4247-9b6b-0566a44449cdKnud<p>Thanks. Was pointed in the same direction by a Nordic support engineer and indeed that was the problem.<br /><br />My dilemma now is why was it ever working? I looked at when I modified the `sdk_config.h` and created the first bootloader image, and it was back on Dec 20. I&#39;ve been using that for testing ever since and never had the readback block.&nbsp;<br /><br />Probably not worth fussing over as clearly the NRF_BL_DEBUG_PORT_DISABLE setting needed to be done (0).<br /><br />I&#39;d like to humbly suggest that a discussion of this setting be added to the <a href="https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader">Getting Started</a> guide.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/232105?ContentTypeID=1Fri, 31 Jan 2020 14:06:28 GMT137ad170-7792-4731-bb38-c0d22fbe4515:17050521-ca67-4941-9d13-ff7499bd44d5Einar Thorsrud<p>Hi Steven,</p> <p>The only explanation I can think of is if the&nbsp;hex you are programming contains data in the APPROTECT register in UICR. Did you build the bootloader with&nbsp;NRF_BL_DEBUG_PORT_DISABLE set to 1 in sdk_config.h?</p> <p>Einar</p><div style="clear:both;"></div>