https://devzone.nordicsemi.com/f/nordic-q-a/8164/ios-toolbox-app---dfu-problem-showing-enable-service-changed-indicationSoftDevice : S110 7.1 SDK 7.2 Example : nrf51-ble-app-temp Using IAR 7.1 (Before debugging with IAR, I downloaded both the bootloader example and S110 7.1) Modified SDK files : bootloader_util_arm.c (copieden-USTelligent Community 13Tue, 14 Jul 2015 09:22:38 GMThttps://devzone.nordicsemi.com/thread/29345?ContentTypeID=1Tue, 14 Jul 2015 09:22:38 GMT137ad170-7792-4731-bb38-c0d22fbe4515:931c222a-c6b5-4074-a988-7caeb4b006e7Hung Bui<p>@Mango922: Please make sure you have enabled IS_SRVC_CHANGED_CHARACT_PRESENT on both application and on the bootloader.</p> <p>If you have, before, run application without the service changed you may need to do a &quot;Bluetooth reset&quot; but it&#39;s not what you showed on the screen. What you should do is simply turn off and on Bluetooth.</p><div style="clear:both;"></div>