diff --git a/wled00/FX_fcn.cpp b/wled00/FX_fcn.cpp
index 09b2ee517..12faaebd6 100644
--- a/wled00/FX_fcn.cpp
+++ b/wled00/FX_fcn.cpp
@@ -1271,7 +1271,7 @@ void WS2812FX::finalizeInit() {
           bool clash;
           do {
             clash = false;
-            for (const auto pin : defDataPins) {
+            for (const auto &pin : defDataPins) {
               if (pin == defPin[j]) {
                 defPin[j]++;
                 if (defPin[j] < WLED_NUM_PINS) clash = true;
diff --git a/wled00/xml.cpp b/wled00/xml.cpp
index 338e795d4..079c0a91b 100644
--- a/wled00/xml.cpp
+++ b/wled00/xml.cpp
@@ -121,6 +121,7 @@ void fillUMPins(JsonObject &mods)
 void appendGPIOinfo() {
   char nS[8];
 
+  // add usermod pins as d.um_p array
   oappend(SET_F("d.um_p=[-1")); // has to have 1 element
   if (i2c_sda > -1 && i2c_scl > -1) {
     oappend(","); oappend(itoa(i2c_sda,nS,10));
@@ -140,54 +141,41 @@ void appendGPIOinfo() {
   }
   oappend(SET_F("];"));
 
-  // add reserved and usermod pins as d.um_p array
-  #if defined(CONFIG_IDF_TARGET_ESP32S2)
-  oappend(SET_F("d.rsvd=[22,23,24,25,26,27,28,29,30,31,32"));
-  #elif defined(CONFIG_IDF_TARGET_ESP32S3)
-  oappend(SET_F("d.rsvd=[19,20,22,23,24,25,26,27,28,29,30,31,32"));  // includes 19+20 for USB OTG (JTAG)
-  if (psramFound()) oappend(SET_F(",33,34,35,36,37")); // in use for "octal" PSRAM or "octal" FLASH -seems that octal PSRAM is very common on S3.
-  #elif defined(CONFIG_IDF_TARGET_ESP32C3)
-  oappend(SET_F("d.rsvd=[11,12,13,14,15,16,17"));
-  #elif defined(ESP32)
-  oappend(SET_F("d.rsvd=[6,7,8,9,10,11,24,28,29,30,31,37,38"));
-  if (!pinManager.isPinOk(16,false)) oappend(SET_F(",16")); // covers PICO & WROVER
-  if (!pinManager.isPinOk(17,false)) oappend(SET_F(",17")); // covers PICO & WROVER
-  #else
-  oappend(SET_F("d.rsvd=[6,7,8,9,10,11"));
-  #endif
-
+  // add reserved (unusable) pins
+  oappend(SET_F("d.rsvd=["));
+  for (unsigned i = 0; i < WLED_NUM_PINS; i++) {
+    if (!pinManager.isPinOk(i, false)) {  // include readonly pins
+      oappendi(i); oappend(",");
+    }
+  }
   #ifdef WLED_ENABLE_DMX
-  oappend(SET_F(",2")); // DMX hardcoded pin
+  oappend(SET_F("2,")); // DMX hardcoded pin
   #endif
-
   #if defined(WLED_DEBUG) && !defined(WLED_DEBUG_HOST)
-  oappend(SET_F(",")); oappend(itoa(hardwareTX,nS,10)); // debug output (TX) pin
+  oappend(itoa(hardwareTX,nS,10)); oappend(","); // debug output (TX) pin
   #endif
-
   //Note: Using pin 3 (RX) disables Adalight / Serial JSON
-
   #ifdef WLED_USE_ETHERNET
   if (ethernetType != WLED_ETH_NONE && ethernetType < WLED_NUM_ETH_TYPES) {
-    for (unsigned p=0; p<WLED_ETH_RSVD_PINS_COUNT; p++) { oappend(","); oappend(itoa(esp32_nonconfigurable_ethernet_pins[p].pin,nS,10)); }
-    if (ethernetBoards[ethernetType].eth_power>=0)     { oappend(","); oappend(itoa(ethernetBoards[ethernetType].eth_power,nS,10)); }
-    if (ethernetBoards[ethernetType].eth_mdc>=0)       { oappend(","); oappend(itoa(ethernetBoards[ethernetType].eth_mdc,nS,10)); }
-    if (ethernetBoards[ethernetType].eth_mdio>=0)      { oappend(","); oappend(itoa(ethernetBoards[ethernetType].eth_mdio,nS,10)); }
-    switch (ethernetBoards[ethernetType].eth_clk_mode) {
+    for (unsigned p=0; p<WLED_ETH_RSVD_PINS_COUNT; p++) { oappend(itoa(esp32_nonconfigurable_ethernet_pins[p].pin,nS,10)); oappend(","); }
+    if (ethernetBoards[ethernetType].eth_power>=0)      { oappend(itoa(ethernetBoards[ethernetType].eth_power,nS,10)); oappend(","); }
+    if (ethernetBoards[ethernetType].eth_mdc>=0)        { oappend(itoa(ethernetBoards[ethernetType].eth_mdc,nS,10)); oappend(","); }
+    if (ethernetBoards[ethernetType].eth_mdio>=0)       { oappend(itoa(ethernetBoards[ethernetType].eth_mdio,nS,10)); oappend(","); }
+    switch (ethernetBoards[ethernetType].eth_clk_mode)  {
       case ETH_CLOCK_GPIO0_IN:
       case ETH_CLOCK_GPIO0_OUT:
-        oappend(SET_F(",0"));
+        oappend(SET_F("0"));
         break;
       case ETH_CLOCK_GPIO16_OUT:
-        oappend(SET_F(",16"));
+        oappend(SET_F("16"));
         break;
       case ETH_CLOCK_GPIO17_OUT:
-        oappend(SET_F(",17"));
+        oappend(SET_F("17"));
         break;
     }
   }
   #endif
-
-  oappend(SET_F("];"));
+  oappend(SET_F("];")); // rsvd
 
   // add info for read-only GPIO
   oappend(SET_F("d.ro_gpio=["));