https://devzone.nordicsemi.com/f/nordic-q-a/52212/what-do-to-when-you-can-t-flash-on-the-nordic-nrf52-dkhello, below is the error experienced. nrfjprog --family NRF52 --eraseall ERROR: JLinkARM DLL reported an error. Try again. If error condition ERROR: persists, run the same command again with argument --log, contact Nordic ERROR: Semiconductor anden-USTelligent Community 13Mon, 16 Sep 2019 20:45:09 GMThttps://devzone.nordicsemi.com/thread/209944?ContentTypeID=1Mon, 16 Sep 2019 20:45:09 GMT137ad170-7792-4731-bb38-c0d22fbe4515:bb1d5206-69cb-4e5c-aafa-1368eac8173aawneil[quote userid="83420" url="~/f/nordic-q-a/52212/what-do-to-when-you-can-t-flash-on-the-nordic-nrf52-dk"]does the nRF52 DK have problems in win10 running under a UBUNTU virtual box?[/quote] <p>The DK is the little blue board - it&#39;s external to Windows, Linux, and VMs!</p> <p>Segger have native support for J-Link on Linux - have you tried that?</p> <p>That would narrow it down a bit ...</p> [quote userid="83420" url="~/f/nordic-q-a/52212/what-do-to-when-you-can-t-flash-on-the-nordic-nrf52-dk"]Cannot connect to J-Link via USB[/quote] <p>So the problem is in the USB connection from the PC to the J-Link.</p><div style="clear:both;"></div>