https://devzone.nordicsemi.com/f/nordic-q-a/26165/i-d-like-to-change-characteristic-uuid-not-based-service-uuidHello I have some problem that I want to change Characteristic UUID different from Service UUID. Like, Service UUID : 11111111 - 1111 -1111 -1111 -111111111111 Charcteristic UUID : 11111111 - 1111 -1111 -1111 -111111115555 I already readen-USTelligent Community 13Mon, 23 Oct 2017 08:35:37 GMThttps://devzone.nordicsemi.com/thread/103074?ContentTypeID=1Mon, 23 Oct 2017 08:35:37 GMT137ad170-7792-4731-bb38-c0d22fbe4515:65794aba-5132-432f-97e5-1f649bf198bdendnode<p><a href="https://devzone.nordicsemi.com/question/151302/discovery-of-128bit-uuid-services-confusing/?answer=151429#post-id-151429">This post</a> should hint how UUIDs work in Nordic stack (always pair of 128-bit base and 16-bit &quot;short&quot; UUID). If for whatever reason you want to set Service or Characteristic (all GATT &quot;objects&quot; are independent so you can assign whatever UUID to whatever object) with new custom 128-bit UUID (as you suggest = altering UUIDs in the end means completely different 128-bit UUID base) then you do the same steps as always:</p> <ol> <li>Provision it to Nordic stack through <code>sd_ble_uuid_vs_add</code> function call.</li> <li>Make sure that FW still compiles and boots (ATT UUID table is dynamic so you need to adjust SD RAM space if you grow it over certain limit set by your previous configuration).</li> <li>Use new UUID base index when provisioning any GATT object which has UUID derived from it.</li> </ol> <p>Looks simple, doesn&#39;t it?</p><div style="clear:both;"></div>