change device name through BLE

Build a custom BLE service and enable the write attribute

Configure the characteristic "attr_char_value.max_len = MAX_LEN"; max_len should be larger than your device name

In the BLE event handler, read back the data like below

 if ((write_evt->handle == m_custom_service_char.value_handle) && (write_evt->data[0] == RENAME))
 {
 				//device name limited to 10bytes
 				for (uint8_t i = 0; i < MAX_DEVICE_NAME_LEN; i++){
 					device_name[i] = write_evt->data[i+1];
 				}

 				ble_gap_conn_sec_mode_t sec_mode;
 				BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);
 				err_code = sd_ble_gap_device_name_set(&sec_mode,(const uint8_t *)device_name,MAX_DEVICE_NAME_LEN);
 				APP_ERROR_CHECK(err_code);
 }