diff --git a/wled00/FX.h b/wled00/FX.h
index 430957803..4f2124ce5 100644
--- a/wled00/FX.h
+++ b/wled00/FX.h
@@ -727,8 +727,7 @@ class WS2812FX {  // 96 bytes
       fixInvalidSegments(),
       setPixelColor(int n, uint32_t c),
       show(void),
-      setTargetFps(uint8_t fps),
-      deserializeMap(uint8_t n=0);
+      setTargetFps(uint8_t fps);
 
     void fill(uint32_t c) { for (int i = 0; i < _length; i++) setPixelColor(i, c); } // fill whole strip with color (inline)
     void addEffect(uint8_t id, mode_ptr mode_fn, const char *mode_name); // add effect to the list; defined in FX.cpp
@@ -748,6 +747,7 @@ class WS2812FX {  // 96 bytes
       hasCCTBus(void),
       // return true if the strip is being sent pixel updates
       isUpdating(void),
+      deserializeMap(uint8_t n=0),
       useLedsArray = false;
 
     inline bool isServicing(void) { return _isServicing; }
diff --git a/wled00/FX_2Dfcn.cpp b/wled00/FX_2Dfcn.cpp
index 7745463b3..091d5eede 100644
--- a/wled00/FX_2Dfcn.cpp
+++ b/wled00/FX_2Dfcn.cpp
@@ -87,7 +87,7 @@ void WS2812FX::setUpMatrix() {
       // allowed values are: -1 (missing pixel/no LED attached), 0 (inactive/unused pixel), 1 (active/used pixel)
       char    fileName[32]; strcpy_P(fileName, PSTR("/2d-gaps.json")); // reduce flash footprint
       bool    isFile = WLED_FS.exists(fileName);
-      int     gapSize = 0;
+      size_t  gapSize = 0;
       int8_t *gapTable = nullptr;
 
       if (isFile && requestJSONBufferLock(20)) {
@@ -108,6 +108,7 @@ void WS2812FX::setUpMatrix() {
             }
           }
         }
+        DEBUG_PRINTLN(F("Gaps loaded."));
         releaseJSONBufferLock();
       }
 
@@ -147,7 +148,6 @@ void WS2812FX::setUpMatrix() {
       Segment::maxWidth = _length;
       Segment::maxHeight = 1;
     }
-    resetSegments();
   }
 #else
   isMatrix = false; // no matter what config says
diff --git a/wled00/FX_fcn.cpp b/wled00/FX_fcn.cpp
index ee0e668b4..8b4b025bb 100644
--- a/wled00/FX_fcn.cpp
+++ b/wled00/FX_fcn.cpp
@@ -1417,7 +1417,7 @@ void WS2812FX::makeAutoSegments(bool forceReset) {
     }
     // do we have LEDs after the matrix? (ignore buses)
     if (autoSegments && _length > Segment::maxWidth*Segment::maxHeight /*&& getActiveSegmentsNum() == 2*/) {
-      if (_segments.size() == getLastActiveSegmentId()+1)
+      if (_segments.size() == getLastActiveSegmentId()+1U)
         _segments.push_back(Segment(Segment::maxWidth*Segment::maxHeight, _length));
       else {
         size_t i = getLastActiveSegmentId() + 1;
@@ -1484,6 +1484,7 @@ void WS2812FX::fixInvalidSegments() {
 }
 
 //true if all segments align with a bus, or if a segment covers the total length
+//irrelevant in 2D set-up
 bool WS2812FX::checkSegmentAlignment() {
   bool aligned = false;
   for (segment &seg : _segments) {
@@ -1583,7 +1584,7 @@ void WS2812FX::loadCustomPalettes() {
 }
 
 //load custom mapping table from JSON file (called from finalizeInit() or deserializeState())
-void WS2812FX::deserializeMap(uint8_t n) {
+bool WS2812FX::deserializeMap(uint8_t n) {
   // 2D support creates its own ledmap (on the fly) if a ledmap.json exists it will overwrite built one.
 
   char fileName[32];
@@ -1599,19 +1600,19 @@ void WS2812FX::deserializeMap(uint8_t n) {
       delete[] customMappingTable;
       customMappingTable = nullptr;
     }
-    return;
+    return false;
   }
 
-  if (!requestJSONBufferLock(7)) return;
-
-  DEBUG_PRINT(F("Reading LED map from "));
-  DEBUG_PRINTLN(fileName);
+  if (!requestJSONBufferLock(7)) return false;
 
   if (!readObjectFromFile(fileName, nullptr, &doc)) {
     releaseJSONBufferLock();
-    return; //if file does not exist just exit
+    return false; //if file does not exist just exit
   }
 
+  DEBUG_PRINT(F("Reading LED map from "));
+  DEBUG_PRINTLN(fileName);
+
   // erase old custom ledmap
   if (customMappingTable != nullptr) {
     customMappingSize = 0;
@@ -1629,6 +1630,7 @@ void WS2812FX::deserializeMap(uint8_t n) {
   }
 
   releaseJSONBufferLock();
+  return true;
 }
 
 
diff --git a/wled00/set.cpp b/wled00/set.cpp
index 6c776df21..2a4520e47 100644
--- a/wled00/set.cpp
+++ b/wled00/set.cpp
@@ -645,8 +645,6 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
   if (subPage == 10)
   {
     strip.isMatrix = request->arg(F("SOMP")).toInt();
-    // strip.panelH   = MAX(1,MIN(128,request->arg(F("PH")).toInt()));
-    // strip.panelW   = MAX(1,MIN(128,request->arg(F("PW")).toInt()));
     strip.panel.clear(); // release memory if allocated
     if (strip.isMatrix) {
       strip.panels  = MAX(1,MIN(WLED_MAX_PANELS,request->arg(F("MPC")).toInt()));
@@ -674,6 +672,7 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
         strip.panel.push_back(p);
       }
       strip.setUpMatrix(); // will check limits
+      strip.makeAutoSegments(true);
     } else {
       Segment::maxWidth  = strip.getLengthTotal();
       Segment::maxHeight = 1;
diff --git a/wled00/wled.cpp b/wled00/wled.cpp
index 35894055e..4b4efa201 100644
--- a/wled00/wled.cpp
+++ b/wled00/wled.cpp
@@ -171,15 +171,14 @@ void WLED::loop()
       }
       delete busConfigs[i]; busConfigs[i] = nullptr;
     }
-    strip.finalizeInit();
-    loadLedmap = 0;
+    strip.finalizeInit(); // also loads default ledmap if present
     if (aligned) strip.makeAutoSegments();
     else strip.fixInvalidSegments();
     yield();
     serializeConfig();
   }
   if (loadLedmap >= 0) {
-    strip.deserializeMap(loadLedmap);
+    if (!strip.deserializeMap(loadLedmap) && strip.isMatrix && loadLedmap == 0) strip.setUpMatrix();
     loadLedmap = -1;
   }