diff --git a/core/input/gamepad_device.cpp b/core/input/gamepad_device.cpp
index b50cf0408..c7ed9690c 100644
--- a/core/input/gamepad_device.cpp
+++ b/core/input/gamepad_device.cpp
@@ -49,11 +49,11 @@ static FILE *record_input;
 
 bool GamepadDevice::gamepad_btn_input(u32 code, bool pressed)
 {
-	if (_input_detected != NULL && _detecting_button 
+	if (_input_detected != nullptr && _detecting_button
 			&& os_GetSeconds() >= _detection_start_time && pressed)
 	{
 		_input_detected(code);
-		_input_detected = NULL;
+		_input_detected = nullptr;
 	}
 	if (!input_mapper || _maple_port < 0 || _maple_port >= (int)ARRAY_SIZE(kcode))
 		return false;
@@ -260,9 +260,11 @@ unsigned int GamepadDevice::get_axis_range(u32 axis) {
 	return it->second;
 }
 
-std::string GamepadDevice::make_mapping_filename()
+std::string GamepadDevice::make_mapping_filename(bool instance)
 {
 	std::string mapping_file = api_name() + "_" + name();
+	if (instance)
+		mapping_file += "-" + _unique_id;
 	std::replace(mapping_file.begin(), mapping_file.end(), '/', '-');
 	std::replace(mapping_file.begin(), mapping_file.end(), '\\', '-');
 	std::replace(mapping_file.begin(), mapping_file.end(), ':', '-');
@@ -277,15 +279,20 @@ std::string GamepadDevice::make_mapping_filename()
 	return mapping_file;
 }
 
-bool GamepadDevice::find_mapping(const char *custom_mapping /* = NULL */)
+bool GamepadDevice::find_mapping(const char *custom_mapping /* = nullptr */)
 {
 	std::string mapping_file;
-	if (custom_mapping != NULL)
+	if (custom_mapping != nullptr)
 		mapping_file = custom_mapping;
 	else
-		mapping_file = make_mapping_filename();
+		mapping_file = make_mapping_filename(true);
 
 	input_mapper = InputMapping::LoadMapping(mapping_file.c_str());
+	if (!input_mapper && custom_mapping == nullptr)
+	{
+		mapping_file = make_mapping_filename(false);
+		input_mapper = InputMapping::LoadMapping(mapping_file.c_str());
+	}
 	return !!input_mapper;
 }
 
diff --git a/core/input/gamepad_device.h b/core/input/gamepad_device.h
index 47d229fa1..34b9a38a7 100644
--- a/core/input/gamepad_device.h
+++ b/core/input/gamepad_device.h
@@ -43,7 +43,7 @@ public:
 	void detect_axis_input(input_detected_cb axis_moved);
 	void cancel_detect_input()
 	{
-		_input_detected = NULL;
+		_input_detected = nullptr;
 	}
 	std::shared_ptr<InputMapping> get_input_mapping() { return input_mapper; }
 	void save_mapping();
@@ -67,7 +67,7 @@ protected:
 		: _api_name(api_name), _maple_port(maple_port), _input_detected(nullptr), _remappable(remappable)
 	{
 	}
-	bool find_mapping(const char *custom_mapping = NULL);
+	bool find_mapping(const char *custom_mapping = nullptr);
 
 	virtual void load_axis_min_max(u32 axis) {}
 
@@ -81,7 +81,7 @@ protected:
 private:
 	int get_axis_min_value(u32 axis);
 	unsigned int get_axis_range(u32 axis);
-	std::string make_mapping_filename();
+	std::string make_mapping_filename(bool instance = false);
 
 	std::string _api_name;
 	int _maple_port;
diff --git a/core/rend/gui.cpp b/core/rend/gui.cpp
index 4fb8cb7a3..5058a21b3 100644
--- a/core/rend/gui.cpp
+++ b/core/rend/gui.cpp
@@ -438,24 +438,42 @@ static const char *maple_expansion_device_name(MapleDeviceType type)
 }
 
 const char *maple_ports[] = { "None", "A", "B", "C", "D" };
-const DreamcastKey button_keys[] = { DC_BTN_START, DC_BTN_A, DC_BTN_B, DC_BTN_X, DC_BTN_Y, DC_DPAD_UP, DC_DPAD_DOWN, DC_DPAD_LEFT, DC_DPAD_RIGHT,
+const DreamcastKey button_keys[] = {
+		DC_BTN_START, DC_BTN_A, DC_BTN_B, DC_BTN_X, DC_BTN_Y, DC_DPAD_UP, DC_DPAD_DOWN, DC_DPAD_LEFT, DC_DPAD_RIGHT,
 		EMU_BTN_MENU, EMU_BTN_ESCAPE, EMU_BTN_FFORWARD, EMU_BTN_TRIGGER_LEFT, EMU_BTN_TRIGGER_RIGHT,
 		DC_BTN_C, DC_BTN_D, DC_BTN_Z, DC_DPAD2_UP, DC_DPAD2_DOWN, DC_DPAD2_LEFT, DC_DPAD2_RIGHT,
-		EMU_BTN_ANA_UP, EMU_BTN_ANA_DOWN, EMU_BTN_ANA_LEFT, EMU_BTN_ANA_RIGHT };
-const char *button_names[] = { "Start", "A", "B", "X", "Y", "DPad Up", "DPad Down", "DPad Left", "DPad Right",
+		EMU_BTN_ANA_UP, EMU_BTN_ANA_DOWN, EMU_BTN_ANA_LEFT, EMU_BTN_ANA_RIGHT
+};
+const char *button_names[] = {
+		"Start", "A", "B", "X", "Y", "DPad Up", "DPad Down", "DPad Left", "DPad Right",
 		"Menu", "Exit", "Fast-forward", "Left Trigger", "Right Trigger",
 		"C", "D", "Z", "Right Dpad Up", "Right DPad Down", "Right DPad Left", "Right DPad Right",
-		"Left Stick Up", "Left Stick Down", "Left Stick Left", "Left Stick Right" };
-const char *arcade_button_names[] = { "Start", "Button 1", "Button 2", "Button 3", "Button 4", "Up", "Down", "Left", "Right",
+		"Left Stick Up", "Left Stick Down", "Left Stick Left", "Left Stick Right"
+};
+const char *arcade_button_names[] = {
+		"Start", "Button 1", "Button 2", "Button 3", "Button 4", "Up", "Down", "Left", "Right",
 		"Menu", "Exit", "Fast-forward", "N/A", "N/A",
-		"Service", "Coin", "Test", "Button 5", "Button 6", "Button 7", "Button 8", "N/A", "N/A", "N/A", "N/A" };
-const DreamcastKey axis_keys[] = { DC_AXIS_X, DC_AXIS_Y, DC_AXIS_LT, DC_AXIS_RT, DC_AXIS_X2, DC_AXIS_Y2, EMU_AXIS_DPAD1_X, EMU_AXIS_DPAD1_Y, EMU_AXIS_DPAD2_X, EMU_AXIS_DPAD2_Y,
-        EMU_AXIS_BTN_START, EMU_AXIS_BTN_A, EMU_AXIS_BTN_B, EMU_AXIS_BTN_X, EMU_AXIS_BTN_Y, EMU_AXIS_DPAD_UP, EMU_AXIS_DPAD_DOWN, EMU_AXIS_DPAD_LEFT, EMU_AXIS_DPAD_RIGHT,
-        EMU_AXIS_BTN_C, EMU_AXIS_BTN_D, EMU_AXIS_BTN_Z, EMU_AXIS_DPAD2_UP, EMU_AXIS_DPAD2_DOWN, EMU_AXIS_DPAD2_LEFT, EMU_AXIS_DPAD2_RIGHT};
-const char *axis_names[] = { "Left Stick X", "Left Stick Y", "Left Trigger", "Right Trigger", "Right Stick X", "Right Stick Y", "DPad X", "DPad Y", "Right DPad X", "Right DPad Y",
-        "Start", "A", "B", "X", "Y", "DPad Up", "DPad Down", "DPad Left", "DPad Right", "C", "D", "Z", "Right DPad Up", "Right DPad Down", "Right DPad Left", "Right DPad Right"};
-const char *arcade_axis_names[] = { "N/A", "N/A", "N/A", "N/A", "N/A", "N/A", "N/A", "N/A", "N/A", "N/A", "Start", "Button 1", "Button 2", "Button 3", "Button 4", "Up", "Down", "Left", "Right",
-		"Service", "Coin", "Test", "Button 5", "Button 6", "Button 7", "Button 8"};
+		"Service", "Coin", "Test", "Button 5", "Button 6", "Button 7", "Button 8", "N/A", "N/A", "N/A", "N/A"
+};
+const DreamcastKey axis_keys[] = {
+		DC_AXIS_X, DC_AXIS_Y, DC_AXIS_LT, DC_AXIS_RT, DC_AXIS_X2, DC_AXIS_Y2, EMU_AXIS_DPAD1_X, EMU_AXIS_DPAD1_Y,
+		EMU_AXIS_DPAD2_X, EMU_AXIS_DPAD2_Y, EMU_AXIS_BTN_START, EMU_AXIS_BTN_A, EMU_AXIS_BTN_B, EMU_AXIS_BTN_X, EMU_AXIS_BTN_Y,
+		EMU_AXIS_BTN_C, EMU_AXIS_BTN_D, EMU_AXIS_BTN_Z, EMU_AXIS_DPAD2_UP, EMU_AXIS_DPAD2_DOWN, EMU_AXIS_DPAD2_LEFT, EMU_AXIS_DPAD2_RIGHT
+};
+const char *axis_names[] = {
+		"Left Stick X", "Left Stick Y", "Left Trigger", "Right Trigger", "Right Stick X", "Right Stick Y", "DPad X", "DPad Y",
+		"Right DPad X", "Right DPad Y", "Start", "A", "B", "X", "Y",
+		"C", "D", "Z", "N/A", "N/A", "N/A", "N/A"
+};
+const char *arcade_axis_names[] = {
+		"Left Stick X", "Left Stick Y", "Left Trigger", "Right Trigger", "Right Stick X", "Right Stick Y", "DPad X", "DPad Y",
+		"Right DPad X", "Right DPad Y", "Start", "Button 1", "Button 2", "Button 3", "Button 4",
+		"Service", "Coin", "Test", "Button 5", "Button 6", "Button 7", "Button 8"
+};
+static_assert(ARRAY_SIZE(button_keys) == ARRAY_SIZE(button_names), "invalid size");
+static_assert(ARRAY_SIZE(button_keys) == ARRAY_SIZE(arcade_button_names), "invalid size");
+static_assert(ARRAY_SIZE(axis_keys) == ARRAY_SIZE(axis_names), "invalid size");
+static_assert(ARRAY_SIZE(axis_keys) == ARRAY_SIZE(arcade_axis_names), "invalid size");
 
 static MapleDeviceType maple_expansion_device_type_from_index(int idx)
 {