https://devzone.nordicsemi.com/f/nordic-q-a/6752/incorrect-file-on-nrf51822-download-tabSo, we have been developing our firmware (for a while now) against a SoftDevice version called 6.0.0-1 alpha. We are getting close to production time, so we wanted to switch to the latest 6.x.x version, and we see that there is a 6.2.1 available on theen-USTelligent Community 13Tue, 28 Apr 2015 14:03:41 GMThttps://devzone.nordicsemi.com/thread/23710?ContentTypeID=1Tue, 28 Apr 2015 14:03:41 GMT137ad170-7792-4731-bb38-c0d22fbe4515:243e10b8-1518-4a04-b627-d8af9bb01bfeRK<p>Having seen the comment above from Hung Bui, you might want to check you have the right file, mine is this</p> <pre><code>-rwxr-xr-x@ 1 xxxx staff 218168 Oct 10 2014 s110_nrf51822_6.2.1/s110_nrf51822_6.2.1_softdevice.hex </code></pre> <p>218168 bytes long.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/23708?ContentTypeID=1Tue, 28 Apr 2015 13:12:12 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8288ba13-6f95-4f3c-9566-428a213acb79Hung Bui<p>@riceman0: In my case nRFGo Studi showed it&#39;s S110 v6.2.1 with Id: 0x0035 You should follow the instruction by RK of recompile the firmware with header files from S110 v6.2.1</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/23709?ContentTypeID=1Tue, 28 Apr 2015 00:19:55 GMT137ad170-7792-4731-bb38-c0d22fbe4515:642dc3ba-9722-4313-89b5-238075ce717dRK<p>Have you recompiled your app against the headers in the 6.2.1 softdevice package you downloaded? There are comments in the releasenotes about API changes and you&#39;re going all the way from a pre-release alpha to a production release about a year newer so a recompile against the correct headers would be advisable anyway.</p> <p>I suspect that nRFgo is just mis-reporting</p><div style="clear:both;"></div>