diff --git a/engines/scumm/detection.cpp b/engines/scumm/detection.cpp
index de9f65065a5..fab985f5651 100644
--- a/engines/scumm/detection.cpp
+++ b/engines/scumm/detection.cpp
@@ -95,8 +95,6 @@ public:
 		return entries;
 	}
 
-	Common::String parseAndCustomizeGuiOptions(const Common::String &optionsString, const Common::String &domain) const override;
-
 	void dumpDetectionEntries() const override final {}
 };
 
@@ -150,7 +148,7 @@ DetectedGames ScummMetaEngineDetection::detectGames(const Common::FSList &fslist
 		// Based on generateComplexID() in advancedDetector.cpp.
 		game.preferredTarget = generatePreferredTarget(*x);
 
-		game.setGUIOptions(x->game.guioptions + MidiDriver::musicType2GUIO(x->game.midi));
+		game.setGUIOptions(customizeGuiOptions(*x));
 		game.appendGUIOptions(getGameGUIOptionsDescriptionLanguage(x->language));
 
 		detectedGames.push_back(game);
@@ -184,51 +182,4 @@ const char *ScummMetaEngineDetection::getOriginalCopyright() const {
 	       "Humongous SCUMM Games (C) Humongous";
 }
 
-Common::String ScummMetaEngineDetection::parseAndCustomizeGuiOptions(const Common::String &optionsString, const Common::String &domain) const {
-	Common::String result = MetaEngineDetection::parseAndCustomizeGuiOptions(optionsString, domain);
-	const char *defaultRenderOption = nullptr;
-
-	const Common::Platform platform = Common::parsePlatform(ConfMan.get("platform", domain));
-	const Common::String extra = ConfMan.get("extra", domain);
-
-	// Add default rendermode option for target. We don't put the default mode into the
-	// detection tables, due to the amount of targets we have. It it more convenient to
-	// add the option here.
-	switch (platform) {
-	case Common::kPlatformAmiga:
-		defaultRenderOption = GUIO_RENDERAMIGA;
-		break;
-	case Common::kPlatformApple2GS:
-		defaultRenderOption = GUIO_RENDERAPPLE2GS;
-		break;
-	case Common::kPlatformMacintosh:
-		defaultRenderOption = GUIO_RENDERMACINTOSH;
-		break;
-	case Common::kPlatformFMTowns:
-		defaultRenderOption = GUIO_RENDERFMTOWNS;
-		break;
-	case Common::kPlatformAtariST:
-		defaultRenderOption = GUIO_RENDERATARIST;
-		break;
-	case Common::kPlatformDOS:
-		defaultRenderOption = (extra.equalsIgnoreCase("EGA") || extra.equalsIgnoreCase("V1") || extra.equalsIgnoreCase("V2")) ? GUIO_RENDEREGA : GUIO_RENDERVGA;
-		break;
-	case Common::kPlatformUnknown:
-		// For targets that don't specify the platform (often happens with SCUMM6+ games) we stick with default VGA.
-		defaultRenderOption = GUIO_RENDERVGA;
-		break;
-	default:
-		// Leave this as nullptr for platforms that don't have a specific render option (SegaCD, NES, ...).
-		// These targets will then have the full set of render mode options in the launcher options dialog.
-		break;
-	}
-
-	// If the render option is already part of the string (specified in the
-	// detection tables) we don't add it again.
-	if (defaultRenderOption != nullptr && !result.contains(defaultRenderOption))
-		result += defaultRenderOption;
-
-	return result;
-}
-
 REGISTER_PLUGIN_STATIC(SCUMM_DETECTION, PLUGIN_TYPE_ENGINE_DETECTION, ScummMetaEngineDetection);
diff --git a/engines/scumm/detection_internal.h b/engines/scumm/detection_internal.h
index 70ecd8d9db1..4b5e10c0dfe 100644
--- a/engines/scumm/detection_internal.h
+++ b/engines/scumm/detection_internal.h
@@ -859,6 +859,49 @@ static bool testGame(const GameSettings *g, const DescMap &fileMD5Map, const Com
 	return true;
 }
 
+static Common::String customizeGuiOptions(const DetectorResult &res) {
+	Common::String guiOptions = res.game.guioptions + MidiDriver::musicType2GUIO(res.game.midi);
+	Common::String defaultRenderOption = "";
+
+	// Add default rendermode option for target. We don't put the default mode into the
+	// detection tables, due to the amount of targets we have. It it more convenient to
+	// add the option here.
+	switch (res.game.platform) {
+	case Common::kPlatformAmiga:
+		defaultRenderOption = GUIO_RENDERAMIGA;
+		break;
+	case Common::kPlatformApple2GS:
+		defaultRenderOption = GUIO_RENDERAPPLE2GS;
+		break;
+	case Common::kPlatformMacintosh:
+		defaultRenderOption = GUIO_RENDERMACINTOSH;
+		break;
+	case Common::kPlatformFMTowns:
+		defaultRenderOption = GUIO_RENDERFMTOWNS;
+		break;
+	case Common::kPlatformAtariST:
+		defaultRenderOption = GUIO_RENDERATARIST;
+		break;
+	case Common::kPlatformDOS:
+		defaultRenderOption = (!strcmp(res.extra, "EGA") || !strcmp(res.extra, "V1") || !strcmp(res.extra, "V2")) ? GUIO_RENDEREGA : GUIO_RENDERVGA;
+		break;
+	case Common::kPlatformUnknown:
+		// For targets that don't specify the platform (often happens with SCUMM6+ games) we stick with default VGA.
+		defaultRenderOption = GUIO_RENDERVGA;
+		break;
+	default:
+		// Leave this as nullptr for platforms that don't have a specific render option (SegaCD, NES, ...).
+		// These targets will then have the full set of render mode options in the launcher options dialog.
+		break;
+	}
+
+	// If the render option is already part of the string (specified in the
+	// detection tables) we don't add it again.
+	if (!guiOptions.contains(defaultRenderOption))
+		guiOptions += defaultRenderOption;
+
+	return guiOptions;
+}
 
 } // End of namespace Scumm
 
diff --git a/engines/scumm/metaengine.cpp b/engines/scumm/metaengine.cpp
index d7dd448fe46..835189a89a0 100644
--- a/engines/scumm/metaengine.cpp
+++ b/engines/scumm/metaengine.cpp
@@ -367,7 +367,7 @@ Common::Error ScummMetaEngine::createInstance(OSystem *syst, Engine **engine) {
 
 	// If the GUI options were updated, we catch this here and update them in the users config
 	// file transparently.
-	Common::updateGameGUIOptions(res.game.guioptions, getGameGUIOptionsDescriptionLanguage(res.language));
+	Common::updateGameGUIOptions(customizeGuiOptions(res), getGameGUIOptionsDescriptionLanguage(res.language));
 
 	// If the game was added really long ago, it may be missing its "extra"
 	// field. When adding game-specific options, it may be our only way of