diff --git a/core/hw/naomi/m4cartridge.h b/core/hw/naomi/m4cartridge.h
index b2c3947b6..52b5dd031 100644
--- a/core/hw/naomi/m4cartridge.h
+++ b/core/hw/naomi/m4cartridge.h
@@ -62,7 +62,7 @@ private:
 	static const u8 k_sboxes[4][16];
 
 	u16 m4id;
-	u8 *m_key_data;			// 2048 bytes
+	u8 *m_key_data = NULL;			// 2048 bytes
 	u16 subkey1, subkey2;
 	u16 one_round[0x10000];
 
diff --git a/core/hw/naomi/naomi_cart.cpp b/core/hw/naomi/naomi_cart.cpp
index aea8b5e39..f91324d62 100644
--- a/core/hw/naomi/naomi_cart.cpp
+++ b/core/hw/naomi/naomi_cart.cpp
@@ -164,7 +164,19 @@ static bool naomi_cart_LoadZip(char *filename)
 	}
 
 	struct Game *game = &Games[gameid];
-
+#if DC_PLATFORM == DC_PLATFORM_NAOMI
+	if (game->cart_type == AW)
+	{
+		msgboxf("Atomiswave cartridges are not supported by NAOMI", 0);
+		return false;
+	}
+#else
+	if (game->cart_type != AW)
+	{
+		msgboxf("NAOMI cartridges are not supported by Atomiswave", 0);
+		return false;
+	}
+#endif
 	Archive *archive = OpenArchive(filename);
 	if (archive != NULL)
 		printf("Opened %s\n", filename);