diff --git a/core/hw/maple/maple_jvs.cpp b/core/hw/maple/maple_jvs.cpp
index 73843aa2e..7b53d4bd6 100644
--- a/core/hw/maple/maple_jvs.cpp
+++ b/core/hw/maple/maple_jvs.cpp
@@ -147,8 +147,8 @@ public:
 	virtual ~jvs_io_board() = default;
 
 	u32 handle_jvs_message(u8 *buffer_in, u32 length_in, u8 *buffer_out);
-	void serialize(Serializer& ser) const;
-	void deserialize(Deserializer& deser);
+	virtual void serialize(Serializer& ser) const;
+	virtual void deserialize(Deserializer& deser);
 
 	bool lightgun_as_analog = false;
 
@@ -373,6 +373,20 @@ public:
 	{
 	}
 
+	void serialize(Serializer& ser) const override
+	{
+		ser << out;
+		jvs_837_13844::serialize(ser);
+	}
+	void deserialize(Deserializer& deser) override
+	{
+		if (deser.version() >= Deserializer::V31)
+			deser >> out;
+		else
+			out = 0xff;
+		jvs_837_13844::deserialize(deser);
+	}
+
 protected:
 	void read_digital_in(const u32 *buttons, u16 *v) override
 	{
@@ -466,6 +480,21 @@ public:
 	{
 	}
 
+	void serialize(Serializer& ser) const override
+	{
+		ser << gear;
+		ser << testMode;
+		jvs_837_13844_motor_board::serialize(ser);
+	}
+	void deserialize(Deserializer& deser) override
+	{
+		if (deser.version() >= Deserializer::V31) {
+			deser >> gear;
+			deser >> testMode;
+		}
+		jvs_837_13844_motor_board::deserialize(deser);
+	}
+
 protected:
 	void read_digital_in(const u32 *buttons, u16 *v) override
 	{
@@ -543,8 +572,8 @@ protected:
 	}
 
 private:
-	bool testMode = false;	// TODO serialize
-	int gear = 0;	// 0: low, 1: high, -1: reverse
+	bool testMode = false;
+	int8_t gear = 0;	// 0: low, 1: high, -1: reverse
 	bool transitionWait = false;
 };
 
diff --git a/core/serialize.h b/core/serialize.h
index fbed29f6a..d85a85868 100644
--- a/core/serialize.h
+++ b/core/serialize.h
@@ -66,7 +66,8 @@ public:
 		V28,
 		V29,
 		V30,
-		Current = V30,
+		V31,
+		Current = V31,
 
 		Next = Current + 1,
 	};