diff --git a/src/common/scripting/interface/vmnatives.cpp b/src/common/scripting/interface/vmnatives.cpp
index 096722e76..1df737d16 100644
--- a/src/common/scripting/interface/vmnatives.cpp
+++ b/src/common/scripting/interface/vmnatives.cpp
@@ -848,6 +848,13 @@ DEFINE_ACTION_FUNCTION(_Wads, ReadLump)
 	ACTION_RETURN_STRING(isLumpValid ? GetStringFromLump(lump, false) : FString());
 }
 
+DEFINE_ACTION_FUNCTION(_Wads, GetLumpLength)
+{
+	PARAM_PROLOGUE;
+	PARAM_INT(lump);
+	ACTION_RETURN_INT(fileSystem.FileLength(lump));
+}
+
 //==========================================================================
 //
 // CVARs
diff --git a/src/g_game.cpp b/src/g_game.cpp
index 3f30a5788..cda263fbe 100644
--- a/src/g_game.cpp
+++ b/src/g_game.cpp
@@ -1890,12 +1890,12 @@ static bool CheckSingleWad (const char *name, bool &printRequires, bool printwar
 bool G_CheckSaveGameWads (FSerializer &arc, bool printwarn)
 {
 	bool printRequires = false;
-	FString text;
 
-	text = arc.GetString("Game WAD");
-	CheckSingleWad (text.GetChars(), printRequires, printwarn);
-	text = arc.GetString("Map WAD");
-	CheckSingleWad (text.GetChars(), printRequires, printwarn);
+	const char *text = arc.GetString("Game WAD");
+	CheckSingleWad (text, printRequires, printwarn);
+	const char *text2 = arc.GetString("Map WAD");
+	// do not validate the same file twice.
+	if (text != nullptr && text2 != nullptr && stricmp(text, text2) != 0) CheckSingleWad (text2, printRequires, printwarn);
 
 	if (printRequires)
 	{
@@ -2271,11 +2271,8 @@ static void PutSaveWads (FSerializer &arc)
 	arc.AddString("Game WAD", name);
 
 	// Name of wad the map resides in
-	if (fileSystem.GetFileContainer (primaryLevel->lumpnum) > fileSystem.GetIwadNum())
-	{
-		name = fileSystem.GetResourceFileName (fileSystem.GetFileContainer (primaryLevel->lumpnum));
-		arc.AddString("Map WAD", name);
-	}
+	name = fileSystem.GetResourceFileName (fileSystem.GetFileContainer (primaryLevel->lumpnum));
+	arc.AddString("Map WAD", name);
 }
 
 static void PutSaveComment (FSerializer &arc)
diff --git a/src/rendering/hwrenderer/scene/hw_walls.cpp b/src/rendering/hwrenderer/scene/hw_walls.cpp
index ffc7cf1b2..b8efe0872 100644
--- a/src/rendering/hwrenderer/scene/hw_walls.cpp
+++ b/src/rendering/hwrenderer/scene/hw_walls.cpp
@@ -2299,7 +2299,7 @@ void HWWall::Process(HWWallDispatcher *di, FRenderState& state, seg_t *seg, sect
 
 		/* bottom texture */
 		// the back sector's ceiling obstructs part of this wall (specially important for sky sectors)
-		float bfh1a = bch1, bfh2a = bch2;
+		float bfh1a = bfh1, bfh2a = bfh2;
 		if (fch1 < bfh1 && fch2 < bfh2 && (seg->linedef->flags & ML_DRAWFULLHEIGHT) == 0)
 		{
 			bfh1 = fch1;
diff --git a/wadsrc/static/zscript/engine/base.zs b/wadsrc/static/zscript/engine/base.zs
index c0754f705..2644dc197 100644
--- a/wadsrc/static/zscript/engine/base.zs
+++ b/wadsrc/static/zscript/engine/base.zs
@@ -862,6 +862,7 @@ struct Wads	// todo: make FileSystem an alias to 'Wads'
 	native static int FindLump(string name, int startlump = 0, FindLumpNamespace ns = GlobalNamespace);
 	native static int FindLumpFullName(string name, int startlump = 0, bool noext = false);
 	native static string ReadLump(int lump);
+	native static int GetLumpLength(int lump);
 
 	native static int GetNumLumps();
 	native static string GetLumpName(int lump);