diff --git a/src/HAP.cpp b/src/HAP.cpp
index 3bfd322..66910b3 100644
--- a/src/HAP.cpp
+++ b/src/HAP.cpp
@@ -1279,7 +1279,7 @@ int HAPClient::getStatusURL(){
   response+="<tr><td>Max Log Entries:</td><td>" + String(homeSpan.webLog.maxEntries) + "</td></tr>\n"; 
 
   if(homeSpan.weblogCallback)
-    response+=homeSpan.weblogCallback();
+    homeSpan.weblogCallback(response);
 
   response+="</table>\n";
   response+="<p></p>";
diff --git a/src/HomeSpan.h b/src/HomeSpan.h
index b87b263..1c05833 100644
--- a/src/HomeSpan.h
+++ b/src/HomeSpan.h
@@ -232,7 +232,7 @@ class Span{
   uint16_t tcpPortNum=DEFAULT_TCP_PORT;                       // port for TCP communications between HomeKit and HomeSpan
   char qrID[5]="";                                            // Setup ID used for pairing with QR Code
   void (*wifiCallback)()=NULL;                                // optional callback function to invoke once WiFi connectivity is established
-  String (*weblogCallback)()=NULL;                            // optional callback function to invoke after header table in Web Log is produced
+  void (*weblogCallback)(String &)=NULL;                      // optional callback function to invoke after header table in Web Log is produced
   void (*pairCallback)(boolean isPaired)=NULL;                // optional callback function to invoke when pairing is established (true) or lost (false)
   boolean autoStartAPEnabled=false;                           // enables auto start-up of Access Point when WiFi Credentials not found
   void (*apFunction)()=NULL;                                  // optional function to invoke when starting Access Point
@@ -348,7 +348,7 @@ class Span{
   }
 
   Span& setWebLogCSS(const char *css){webLog.css="\n" + String(css) + "\n";return(*this);}
-  Span& setWebLogCallback(String (*f)()){weblogCallback=f;return(*this);}
+  Span& setWebLogCallback(void (*f)(String &)){weblogCallback=f;return(*this);}
 
   void autoPoll(uint32_t stackSize=8192, uint32_t priority=1, uint32_t cpu=0){     // start pollTask()
     xTaskCreateUniversal([](void *parms){for(;;)homeSpan.pollTask();}, "pollTask", stackSize, NULL, priority, &pollTaskHandle, cpu);
diff --git a/src/src.ino b/src/src.ino
index 478542b..5bf602d 100644
--- a/src/src.ino
+++ b/src/src.ino
@@ -48,11 +48,9 @@ struct LED_Service : Service::LightBulb {
 
 //////////////////////////////////////
 
-String extraData(){
-  String r;
+void extraData(String &r){
   r+="<tr><td>Free RAM:</td><td>" + String((double)(esp_get_free_internal_heap_size() / 1024),2) + " Kb (" + String(esp_get_free_internal_heap_size()) + " bytes)</td></tr>\n"; 
   r+="<tr><td>Free PSRAM:</td><td>" + String((double)(esp_get_free_heap_size() / 1024 / 1024),2) + " Mb (" + String(esp_get_free_heap_size()) + " bytes)</td></tr>\n";
-  return(r);
 }
 
 //////////////////////////////////////