diff --git a/tasmota/support_esp.ino b/tasmota/support_esp.ino
index dca558cb6..57ad66046 100644
--- a/tasmota/support_esp.ino
+++ b/tasmota/support_esp.ino
@@ -461,11 +461,6 @@ uint32_t ESP_getChipId(void) {
   return id;
 }
 
-uint32_t ESP_getFreeSketchSpace(void) {
-  uint32_t size = EspRunningFactoryPartition();
-  return (size) ? size : ESP.getFreeSketchSpace();
-}
-
 uint32_t ESP_getSketchSize(void) {
   static uint32_t sketchsize = 0;
 
@@ -475,6 +470,17 @@ uint32_t ESP_getSketchSize(void) {
   return sketchsize;
 }
 
+uint32_t ESP_getFreeSketchSpace(void) {
+  if (EspSingleOtaPartition()) {
+    uint32_t size = EspRunningFactoryPartition();
+    if (!size) {
+      size = ESP.getFreeSketchSpace();
+    }
+    return size - ESP_getSketchSize();
+  }
+  return ESP.getFreeSketchSpace();
+}
+
 uint32_t ESP_getFreeHeap(void) {
   // ESP_getFreeHeap() returns also IRAM which we don't use
   return heap_caps_get_free_size(MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);