diff --git a/wled00/FX_2Dfcn.cpp b/wled00/FX_2Dfcn.cpp
index a8545113..9491e134 100644
--- a/wled00/FX_2Dfcn.cpp
+++ b/wled00/FX_2Dfcn.cpp
@@ -249,7 +249,7 @@ void IRAM_ATTR __attribute__((hot)) Segment::setPixelColorXY_fast(int x, int y,
   }
 
 #if 0 // this is still a dangerous optimization
-  if ((i < UINT_MAX) && sameColor && (call > 0) && (!transitional)  && (mode != FX_MODE_2DSCROLLTEXT) && (ledsrgb[i] == CRGB(scaled_col))) return; // WLEDMM looks like nothing to do
+  if ((i < UINT_MAX) && sameColor && (call > 0) && (!transitional) && (!freeze) && (mode != FX_MODE_2DSCROLLTEXT) && (ledsrgb[i] == CRGB(scaled_col))) return; // WLEDMM looks like nothing to do
 #endif
 
   // handle reverse and transpose
@@ -311,7 +311,7 @@ void IRAM_ATTR_YN Segment::setPixelColorXY(int x, int y, uint32_t col) //WLEDMM:
   }
 
 #if 0 // this is a dangerous optimization
-  if ((i < UINT_MAX) && sameColor && (call > 0) && (!transitional) && (mode != FX_MODE_2DSCROLLTEXT) && (ledsrgb[i] == CRGB(col))) return; // WLEDMM looks like nothing to do
+  if ((i < UINT_MAX) && sameColor && (call > 0) && (!transitional) && (!freeze) && (mode != FX_MODE_2DSCROLLTEXT) && (ledsrgb[i] == CRGB(col))) return; // WLEDMM looks like nothing to do
 #endif
 
   if (reverse  ) x = cols  - x - 1;
diff --git a/wled00/FX_fcn.cpp b/wled00/FX_fcn.cpp
index eb0c97e8..75d7c828 100644
--- a/wled00/FX_fcn.cpp
+++ b/wled00/FX_fcn.cpp
@@ -945,8 +945,7 @@ void IRAM_ATTR_YN WLED_O2_ATTR __attribute__((hot)) Segment::setPixelColor(int i
   int vStrip = i>>16; // hack to allow running on virtual strips (2D segment columns/rows)
 #endif
   i &= 0xFFFF;
-
-  if (i >= virtualLength() || i<0) return;  // if pixel would fall out of segment just exit
+  if (unsigned(i) >= virtualLength()) return;  // if pixel would fall out of segment just exit //WLEDMM unsigned(i)>SEGLEN also catches "i<0"
 
 #ifndef WLED_DISABLE_2D
   if (is2D()) {
@@ -1914,7 +1913,7 @@ void WS2812FX::service() {
     if(nowUp >= seg.next_time || _triggered || (doShow && seg.mode == FX_MODE_STATIC))  // WLEDMM ">=" instead of ">"
     {
       if (seg.grouping == 0) seg.grouping = 1; //sanity check
-      if (!seg.freeze) doShow = true;
+      if ((!seg.freeze) || _triggered) doShow = true;   // WLEDMM "triggered" overrules "freeze"
       uint16_t frameDelay = FRAMETIME;    // WLEDMM avoid name clash with "delay" function
 
       if (!seg.freeze) { //only run effect function if not frozen
@@ -1950,6 +1949,8 @@ void WS2812FX::service() {
     }
     _segment_index++;
   }
+  if (_triggered) doShow = true;      // WLEDMM "triggered" always means "show"
+
   _virtualSegmentLength = 0;
   busses.setSegmentCCT(-1);
   if(doShow) {
diff --git a/wled00/json.cpp b/wled00/json.cpp
index c51deefa..f9f9f5c4 100644
--- a/wled00/json.cpp
+++ b/wled00/json.cpp
@@ -329,6 +329,8 @@ bool deserializeSegment(JsonObject elem, byte it, byte presetId)
     uint8_t oldMap1D2D = seg.map1D2D;
     seg.map1D2D = M12_Pixels; // no mapping
     // WLEDMM begin - we need to init segment caches before putting any pixels
+    auto oldLock = suspendStripService; // remember pevious lock status
+    suspendStripService = true;
     if (strip.isServicing()) {
       USER_PRINTLN(F("deserializeSegment() image: strip is still drawing effects."));
       strip.waitUntilIdle();
@@ -350,6 +352,8 @@ bool deserializeSegment(JsonObject elem, byte it, byte presetId)
     start = 0, stop = 0;
     set = 0; //0 nothing set, 1 start set, 2 range set
 
+    seg.startFrame();   // WLEDMM do it again, to be sure that all segment properties get cached
+    unsigned seg_len = seg.calc_virtualLength(); // WLEDMM prevent out-of-bounds writing
     for (size_t i = 0; i < iarr.size(); i++) {
       if(iarr[i].is<JsonInteger>()) {
         if (!set) {
@@ -375,12 +379,16 @@ bool deserializeSegment(JsonObject elem, byte it, byte presetId)
 
         if (set < 2 || stop <= start) stop = start + 1;
         uint32_t c = gamma32(RGBW32(rgbw[0], rgbw[1], rgbw[2], rgbw[3]));
-        while (start < stop) seg.setPixelColor(start++, c);
+        while (start < stop) {
+          if (unsigned(start) < seg_len) seg.setPixelColor(start, c);  // WLEDMM don't write out-of-bounds
+          start++;
+        }
         set = 0;
       }
     }
     seg.map1D2D = oldMap1D2D; // restore mapping
     strip.trigger(); // force segment update
+    suspendStripService = oldLock; // restore previous lock status
   }
   // send UDP/WS if segment options changed (except selection; will also deselect current preset)
   uint8_t diffresult = seg.differs(prev)  & 0x7F;