diff --git a/src/d_iwad.cpp b/src/d_iwad.cpp
index f10d48fb7..fadb9e65b 100644
--- a/src/d_iwad.cpp
+++ b/src/d_iwad.cpp
@@ -583,7 +583,7 @@ int FIWadManager::IdentifyVersion (TArray<FString> &wadfiles, const char *iwad,
 		// We have a -iwad parameter. Pick the first usable IWAD we found through that.
 		for (unsigned i = numFoundWads; i < mFoundWads.Size(); i++)
 		{
-			if (mFoundWads[i].mInfoIndex > 0)
+			if (mFoundWads[i].mInfoIndex >= 0)
 			{
 				picks.Push(mFoundWads[i]);
 				break;
diff --git a/src/gl/renderer/gl_renderstate.cpp b/src/gl/renderer/gl_renderstate.cpp
index c37ccbb99..86a58a743 100644
--- a/src/gl/renderer/gl_renderstate.cpp
+++ b/src/gl/renderer/gl_renderstate.cpp
@@ -150,6 +150,12 @@ bool FRenderState::ApplyShader()
 		}
 	}
 
+	if (!activeShader)
+	{
+		assert(0); // We should not be getting to this point!
+		return false;
+	}
+
 	glVertexAttrib4fv(VATTR_COLOR, mColor.vec);
 	glVertexAttrib4fv(VATTR_NORMAL, mNormal.vec);
 	//activeShader->muObjectColor2.Set(mObjectColor2);
@@ -374,7 +380,8 @@ void FRenderState::ApplyLightIndex(int index)
 		{
 			index = GLRenderer->mLights->BindUBO(index);
 		}
-		activeShader->muLightIndex.Set(index);
+		if (activeShader)
+			activeShader->muLightIndex.Set(index);
 	}
 }
 
diff --git a/src/gl/shaders/gl_shader.cpp b/src/gl/shaders/gl_shader.cpp
index 41b6c18a1..6c9ee416d 100644
--- a/src/gl/shaders/gl_shader.cpp
+++ b/src/gl/shaders/gl_shader.cpp
@@ -682,6 +682,7 @@ void gl_ParseHardwareShader(FScanner &sc, int deflump)
 
 		PostProcessShader shaderdesc;
 		shaderdesc.Target = sc.String;
+		shaderdesc.Target.ToLower();
 
 		bool validTarget = false;
 		if (sc.Compare("beforebloom")) validTarget = true;
diff --git a/src/gl/textures/gl_texture.cpp b/src/gl/textures/gl_texture.cpp
index e5a91fe14..51425d40d 100644
--- a/src/gl/textures/gl_texture.cpp
+++ b/src/gl/textures/gl_texture.cpp
@@ -564,7 +564,7 @@ void gl_ParseBrightmap(FScanner &sc, int deflump)
 	else sc.UnGet();
 
 	sc.MustGetString();
-	FTextureID no = TexMan.CheckForTexture(sc.String, type);
+	FTextureID no = TexMan.CheckForTexture(sc.String, type, FTextureManager::TEXMAN_TryAny | FTextureManager::TEXMAN_Overridable);
 	FTexture *tex = TexMan[no];
 
 	sc.MustGetToken('{');