https://devzone.nordicsemi.com/f/nordic-q-a/12525/nrf51822-fail-txt-timeoutI recently purchased nrf51-DK. I was going through a getting started document which said to update the firmware on the board. After updating it the boards just keep disconnecting and reconnecting when connected through the USB, there is a fail.txt fileen-USTelligent Community 13Mon, 14 Mar 2016 12:36:33 GMThttps://devzone.nordicsemi.com/thread/47496?ContentTypeID=1Mon, 14 Mar 2016 12:36:33 GMT137ad170-7792-4731-bb38-c0d22fbe4515:335489ef-a604-4cf1-b457-1bdd8a9e6b69Ole Bauck<p>With the nRF5x-OB-JLink-IF file you should be able to upload the code if you choose J-LINK / J-TRACE Cortex debugger under &quot;Options for Target...&quot;-&gt;Debug tab.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/47495?ContentTypeID=1Sun, 13 Mar 2016 02:47:20 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b1e415c0-7a72-446d-8679-78f3e5cefd57zer0c00l<p>I tried <strong>nRF5x-OB-JLink-IF</strong> file, and there is no fail.txt file now, it also does not disconnect and reconnect anymore but I don&#39;t know how to upload my code using Keil with JLINK file. I also tried <strong>nRF5x-OB-mbed-IF 0219</strong>. This also has the same behavior, fail.txt is created, and the board keeps disconnecting</p><div style="clear:both;"></div>