diff --git a/core/hw/naomi/naomi.cpp b/core/hw/naomi/naomi.cpp
index 0227dff0d..5d4c8d563 100644
--- a/core/hw/naomi/naomi.cpp
+++ b/core/hw/naomi/naomi.cpp
@@ -14,8 +14,6 @@
 #include "naomi_cart.h"
 #include "naomi_regs.h"
 
-u32 naomi_updates;
-
 //#define NAOMI_COMM
 
 static const u32 BoardID=0x980055AA;
@@ -372,7 +370,6 @@ u32 reg_dimm_parameterl;
 u32 reg_dimm_parameterh;
 u32 reg_dimm_status = 0x11;
 
-bool NaomiDataRead = false;
 static bool aw_ram_test_skipped = false;
 
 void naomi_process(u32 command, u32 offsetl, u32 parameterl, u32 parameterh)
@@ -428,7 +425,6 @@ void Naomi_DmaStart(u32 addr, u32 data)
 		return;
 	}
 	
-	NaomiDataRead = true;
 	SB_GDST|=data&1;
 
 	if (SB_GDST==1)
@@ -544,7 +540,6 @@ void naomi_reg_Reset(bool hard)
 	SB_GDST = 0;
 	SB_GDEN = 0;
 
-	NaomiDataRead = false;
 	aw_ram_test_skipped = false;
 	GSerialBuffer = 0;
 	BSerialBuffer = 0;
diff --git a/core/hw/naomi/naomi.h b/core/hw/naomi/naomi.h
index 88ae8cb58..61808c658 100644
--- a/core/hw/naomi/naomi.h
+++ b/core/hw/naomi/naomi.h
@@ -23,6 +23,3 @@ extern u32 reg_dimm_offsetl;
 extern u32 reg_dimm_parameterl;
 extern u32 reg_dimm_parameterh;
 extern u32 reg_dimm_status;
-
-extern bool NaomiDataRead;
-extern u32 naomi_updates;
diff --git a/core/hw/naomi/naomi_cart.cpp b/core/hw/naomi/naomi_cart.cpp
index 3efea7e3a..633ca145d 100644
--- a/core/hw/naomi/naomi_cart.cpp
+++ b/core/hw/naomi/naomi_cart.cpp
@@ -703,7 +703,7 @@ u32 NaomiCartridge::ReadMem(u32 address, u32 size)
 	{
 	case 0x3c:	// 5f703c: DIMM COMMAND
 		DEBUG_LOG(NAOMI, "DIMM COMMAND read<%d>", size);
-		return reg_dimm_command | (NaomiDataRead ? 0 : -1); //pretend the board isn't there for the bios
+		return 0xffff; //reg_dimm_command
 	case 0x40:	// 5f7040: DIMM OFFSETL
 		DEBUG_LOG(NAOMI, "DIMM OFFSETL read<%d>", size);
 		return reg_dimm_offsetl;
@@ -789,11 +789,11 @@ u32 NaomiCartridge::ReadMem(u32 address, u32 size)
 
 	case NAOMI_COMM2_STATUS0_addr & 255:
 		DEBUG_LOG(NAOMI, "NAOMI_COMM2_STATUS0 read");
-		return comm_offset_status0;
+		return comm_status0;
 
 	case NAOMI_COMM2_STATUS1_addr & 255:
 		DEBUG_LOG(NAOMI, "NAOMI_COMM2_STATUS1 read");
-		return comm_offset_status1;
+		return comm_status1;
 
 	default:
 		break;
@@ -836,7 +836,6 @@ void NaomiCartridge::WriteMem(u32 address, u32 data, u32 size)
 		if (data&0x100)
 		{
 			asic_CancelInterrupt(holly_EXP_PCI);
-			naomi_updates=100;
 		}
 		else if ((data&1)==0)
 		{
@@ -936,13 +935,13 @@ void NaomiCartridge::WriteMem(u32 address, u32 data, u32 size)
 		return;
 
 	case NAOMI_COMM2_STATUS0_addr & 255:
-		comm_offset_status0 = (u16)data;
-		DEBUG_LOG(NAOMI, "NAOMI_COMM2_STATUS0 set to %x", comm_offset_status0);
+		comm_status0 = (u16)data;
+		DEBUG_LOG(NAOMI, "NAOMI_COMM2_STATUS0 set to %x", comm_status0);
 		return;
 
 	case NAOMI_COMM2_STATUS1_addr & 255:
-		comm_offset_status1 = (u16)data;
-		DEBUG_LOG(NAOMI, "NAOMI_COMM2_STATUS1 set to %x", comm_offset_status1);
+		comm_status1 = (u16)data;
+		DEBUG_LOG(NAOMI, "NAOMI_COMM2_STATUS1 set to %x", comm_status1);
 		return;
 
 	default: break;
diff --git a/core/hw/naomi/naomi_cart.h b/core/hw/naomi/naomi_cart.h
index e4364a8fc..a05042299 100644
--- a/core/hw/naomi/naomi_cart.h
+++ b/core/hw/naomi/naomi_cart.h
@@ -1,5 +1,4 @@
-#ifndef NAOMI_CART_H
-#define NAOMI_CART_H
+#pragma once
 
 #include <string>
 #include "types.h"
@@ -55,8 +54,8 @@ protected:
 	// Naomi 840-0001E communication board
 	u16 comm_ctrl = 0xC000;
 	u16 comm_offset = 0;
-	u16 comm_offset_status0 = 0;
-	u16 comm_offset_status1 = 0;
+	u16 comm_status0 = 0;
+	u16 comm_status1 = 0;
 	u16 m68k_ram[128 * 1024 / sizeof(u16)];
 	u16 comm_ram[64 * 1024 / sizeof(u16)];
 };
@@ -125,5 +124,3 @@ struct InputDescriptors
 };
 
 extern InputDescriptors *NaomiGameInputs;
-
-#endif //NAOMI_CART_H
diff --git a/core/serialize.cpp b/core/serialize.cpp
index f31bd22cc..0acdbb100 100644
--- a/core/serialize.cpp
+++ b/core/serialize.cpp
@@ -240,7 +240,6 @@ extern u32 reg_dimm_offsetl;
 extern u32 reg_dimm_parameterl;
 extern u32 reg_dimm_parameterh;
 extern u32 reg_dimm_status;
-extern bool NaomiDataRead;
 
 bool rc_serialize(void *src, unsigned int src_size, void **dest, unsigned int *total_size)
 {
@@ -538,7 +537,7 @@ bool dc_serialize(void **data, unsigned int *total_size)
 	REICAST_S(reg_dimm_parameterl);
 	REICAST_S(reg_dimm_parameterh);
 	REICAST_S(reg_dimm_status);
-	REICAST_S(NaomiDataRead);
+	REICAST_SKIP(1); // NaomiDataRead
 
 	REICAST_S(settings.dreamcast.broadcast);
 	REICAST_S(settings.dreamcast.cable);
@@ -804,7 +803,7 @@ static bool dc_unserialize_libretro(void **data, unsigned int *total_size)
 	REICAST_US(reg_dimm_parameterl);
 	REICAST_US(reg_dimm_parameterh);
 	REICAST_US(reg_dimm_status);
-	REICAST_US(NaomiDataRead);
+	REICAST_SKIP(1); // NaomiDataRead
 
 	REICAST_US(settings.dreamcast.broadcast);
 	REICAST_US(settings.dreamcast.cable);
@@ -1145,7 +1144,7 @@ bool dc_unserialize(void **data, unsigned int *total_size)
 	REICAST_US(reg_dimm_parameterl);
 	REICAST_US(reg_dimm_parameterh);
 	REICAST_US(reg_dimm_status);
-	REICAST_US(NaomiDataRead);
+	REICAST_SKIP(1); // NaomiDataRead
 
 	if (version < V5)
 	{