https://devzone.nordicsemi.com/f/nordic-q-a/84252/nrf51dk---failed-to-load-readback-protection-status-device-setup-not-foundHi. I am returning to developing on Nordic devices after some time away, enticed back by nrfConnect / VSCode support for MacOS. I am running MacOs Monterey 12.1 and I have installed the latest versions of the nrf Connect, Segger tools and sdk. Afteren-USTelligent Community 13Mon, 31 Jan 2022 20:32:43 GMThttps://devzone.nordicsemi.com/thread/350529?ContentTypeID=1Mon, 31 Jan 2022 20:32:43 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bd35ce0c-0be7-423c-856b-135a23f136c2Gavin<p>OK - now sorted. To use nrf Connect to connect via the nrf51dk usb port, I first needed to replace the mBed firmware on the interface chip with the JLink firmware. Put the interface chip into bootloader mode by holding down the IF BOOT button on power up, and when the BOOTLOADER driver appears, dump the firmware into it, wait for it to finish copying and power cycle the board.<br /><br />You can find a working version of the firmware here on the nrf52 pages:&nbsp;<a href="https://www.nordicsemi.com/Products/Development-hardware/nrf52-dk/download#infotabs">https://www.nordicsemi.com/Products/Development-hardware/nrf52-dk/download#infotabs</a></p> <p>It would be good to download the latest from Segger but it is not clear which file is the correct firmware for the nrf51dk board</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/350523?ContentTypeID=1Mon, 31 Jan 2022 19:55:58 GMT137ad170-7792-4731-bb38-c0d22fbe4515:80f3dcc3-c2f5-4086-baed-83c7157a9c9aGavin<p>Ok. Something has happened and nrfConnect is now able to load the readback protection status via the JLink Lite and offers me the rest of the functionality.</p> <p>HOWEVER I still cannot connect to it via the nrf51dk board&#39;s usb without the JLink Lite</p><div style="clear:both;"></div>