diff --git a/core/hw/maple/maple_devs.cpp b/core/hw/maple/maple_devs.cpp
index f6188b298..699c45ca7 100755
--- a/core/hw/maple/maple_devs.cpp
+++ b/core/hw/maple/maple_devs.cpp
@@ -1418,9 +1418,33 @@ struct atomiswave_lightgun : maple_lightgun
 	}
 };
 
-char EEPROM[0x100];
+u8 EEPROM[0x100];
 bool EEPROM_loaded = false;
 
+void load_naomi_eeprom()
+{
+	if (!EEPROM_loaded)
+	{
+		EEPROM_loaded = true;
+		std::string nvmemSuffix = cfgLoadStr("net", "nvmem", "");
+		std::string eeprom_file = get_game_save_prefix() + nvmemSuffix + ".eeprom";
+		FILE* f = fopen(eeprom_file.c_str(), "rb");
+		if (f)
+		{
+			fread(EEPROM, 1, 0x80, f);
+			fclose(f);
+			DEBUG_LOG(MAPLE, "Loaded EEPROM from %s", eeprom_file.c_str());
+		}
+		else if (naomi_default_eeprom != NULL)
+		{
+			DEBUG_LOG(MAPLE, "Using default EEPROM file");
+			memcpy(EEPROM, naomi_default_eeprom, 0x80);
+		}
+		else
+			DEBUG_LOG(MAPLE, "EEPROM file not found at %s and no default found", eeprom_file.c_str());
+	}
+}
+
 u32 naomi_button_mapping[] = {
 		NAOMI_SERVICE_KEY,	// DC_BTN_C
 		NAOMI_BTN1_KEY,		// DC_BTN_B
@@ -2153,6 +2177,7 @@ struct maple_naomi_jamma : maple_sega_controller
 
 			case 0x0B:	//EEPROM write
 			{
+				load_naomi_eeprom();
 				int address = dma_buffer_in[1];
 				int size = dma_buffer_in[2];
 				DEBUG_LOG(MAPLE, "EEprom write %08X %08X\n", address, size);
@@ -2183,26 +2208,7 @@ struct maple_naomi_jamma : maple_sega_controller
 
 			case 0x3:	//EEPROM read
 			{
-				if (!EEPROM_loaded)
-				{
-					EEPROM_loaded = true;
-					std::string nvmemSuffix = cfgLoadStr("net", "nvmem", "");
-					std::string eeprom_file = get_game_save_prefix() + nvmemSuffix + ".eeprom";
-					FILE* f = fopen(eeprom_file.c_str(), "rb");
-					if (f)
-					{
-						fread(EEPROM, 1, 0x80, f);
-						fclose(f);
-						DEBUG_LOG(MAPLE, "Loaded EEPROM from %s", eeprom_file.c_str());
-					}
-					else if (naomi_default_eeprom != NULL)
-					{
-						DEBUG_LOG(MAPLE, "Using default EEPROM file");
-						memcpy(EEPROM, naomi_default_eeprom, 0x80);
-					}
-					else
-						DEBUG_LOG(MAPLE, "EEPROM file not found at %s and no default found", eeprom_file.c_str());
-				}
+				load_naomi_eeprom();
 				//printf("EEprom READ\n");
 				int address = dma_buffer_in[1];
 				//printState(Command,buffer_in,buffer_in_len);
diff --git a/core/hw/maple/maple_devs.h b/core/hw/maple/maple_devs.h
index 88b750907..d1505381f 100755
--- a/core/hw/maple/maple_devs.h
+++ b/core/hw/maple/maple_devs.h
@@ -133,6 +133,9 @@ void limit_joystick_magnitude(s8& joyx, s8& joyy)
 	}
 }
 
+extern u8 EEPROM[0x100];
+void load_naomi_eeprom();
+
 // Mouse position and buttons
 extern u32 mo_buttons;
 extern s32 mo_x_abs;
diff --git a/core/hw/maple/maple_helper.cpp b/core/hw/maple/maple_helper.cpp
index 12b57c197..095dd5fb9 100644
--- a/core/hw/maple/maple_helper.cpp
+++ b/core/hw/maple/maple_helper.cpp
@@ -1,11 +1,6 @@
 #include "maple_helper.h"
 #include "maple_if.h"
 
-u32 maple_GetBusId(u32 addr)
-{
-	return addr>>6;
-}
-
 u32 maple_GetPort(u32 addr)
 {
 	for (int i=0;i<6;i++)
@@ -26,12 +21,3 @@ u32 maple_GetAttachedDevices(u32 bus)
 
 	return rv;
 }
-
-//device : 0 .. 4 -> subdevice , 5 -> main device :)
-u32 maple_GetAddress(u32 bus,u32 port)
-{
-	u32 rv=bus<<6;
-	rv|=1<<port;
-
-	return rv;
-}
diff --git a/core/hw/maple/maple_helper.h b/core/hw/maple/maple_helper.h
index 8fa011a8e..f852cffbe 100644
--- a/core/hw/maple/maple_helper.h
+++ b/core/hw/maple/maple_helper.h
@@ -1,7 +1,19 @@
 #pragma once
 #include "types.h"
 
-u32 maple_GetBusId(u32 addr);
+static inline u32 maple_GetBusId(u32 addr)
+{
+	return addr >> 6;
+}
+
 u32 maple_GetPort(u32 addr);
 u32 maple_GetAttachedDevices(u32 bus);
-u32 maple_GetAddress(u32 bus,u32 port);
\ No newline at end of file
+
+//device : 0 .. 4 -> subdevice , 5 -> main device :)
+static inline u32 maple_GetAddress(u32 bus, u32 port)
+{
+	u32 rv = bus << 6;
+	rv |= 1 << port;
+
+	return rv;
+}
diff --git a/core/hw/naomi/naomi_flashrom.cpp b/core/hw/naomi/naomi_flashrom.cpp
new file mode 100644
index 000000000..d52e39624
--- /dev/null
+++ b/core/hw/naomi/naomi_flashrom.cpp
@@ -0,0 +1,124 @@
+/*
+	Created on: Apr 19, 2020
+
+	Copyright 2020 flyinghead
+
+	This file is part of flycast.
+
+    flycast is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    flycast is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with flycast.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include "naomi_flashrom.h"
+#include "hw/flashrom/flashrom.h"
+#include "hw/holly/sb_mem.h"
+#include "hw/maple/maple_devs.h"
+
+extern MemChip *sys_nvmem;
+
+static u16 eeprom_crc(const u8 *buf, int size)
+{
+	int n = 0xdebdeb00;
+
+	for (int i = 0; i < size; i++)
+	{
+		n &= 0xffffff00;
+		n += buf[i];
+
+		for (int c = 0; c < 8; c++)
+		{
+			if (n & 0x80000000)
+				n = (n << 1) + 0x10210000;
+			else
+				n <<= 1;
+		}
+	}
+	for (int c = 0; c < 8; c++)
+	{
+		if (n & 0x80000000)
+			n = (n << 1) + 0x10210000;
+		else
+			n <<= 1;
+	}
+
+	return n >> 16;
+}
+
+//
+// bbsram layout:
+// not totally reveng'ed but there's one fixed-size record,
+// followed by a variable-size record starting at 1F8
+// where the interesting stuff is.
+// Offset    Size
+// 0x1f8       2        CRC of bytes [218,218+size[
+// 0x1fa       2        0
+// 0x1fc       4        record size
+// 0x200       4        record padded size (crc is done on this)
+// 0x204       4        0
+// 0x208       16       Same header repeated
+// 0x218    size*2      Record data, repeated twice
+//
+void write_naomi_flash(u32 addr, u8 value)
+{
+	addr &= sys_nvmem->mask;
+	verify(addr >= 0x218);
+	u32 block_size = sys_nvmem->Read(0x200, 4);
+	if (addr >= 0x218 + block_size || 0x218 + block_size * 2 > sys_nvmem->size)
+	{
+		WARN_LOG(NAOMI, "NVMEM record doesn't exist or is too short");
+		return;
+	}
+	sys_nvmem->data[addr] = value;
+	sys_nvmem->data[addr + block_size] = value;
+	u16 crc = eeprom_crc(&sys_nvmem->data[0x218], block_size);
+	*(u16 *)&sys_nvmem->data[0x1f8] = crc;
+	*(u16 *)&sys_nvmem->data[0x208] = crc;
+}
+
+//
+// eeprom layout:
+// Offset    Size
+// 0         2        CRC of bytes [2,17]
+// 2         1        size of record (16, sometimes 1, ignored)
+// 3         15       data
+// 18        18       same record repeated
+// 36        2        CRC of bytes [44,44+size[
+// 38        1        record size
+// 39        1        record padded size (crc is done on this)
+// 40        4        Same header repeated
+// 44     size*2      Record data, repeated twice
+//
+// The first record contains naomi bios settings, and the second one game-specific settings
+//
+void write_naomi_eeprom(u32 offset, u8 value)
+{
+	load_naomi_eeprom();
+	if (offset >= 3 && offset < 20)
+	{
+		EEPROM[offset] = value;
+		EEPROM[offset + 18] = value;
+
+		u16 crc = eeprom_crc((u8 *)EEPROM + 2, 16);
+		*(u16 *)&EEPROM[0] = crc;
+		*(u16 *)&EEPROM[18] = crc;
+	}
+	else if (offset >= 44 && (int)offset - 44 < EEPROM[39])
+	{
+		EEPROM[offset] = value;
+		EEPROM[offset + EEPROM[39]] = value;
+		u16 crc = eeprom_crc((u8 *)EEPROM + 44, EEPROM[39]);
+		*(u16 *)&EEPROM[36] = crc;
+		*(u16 *)&EEPROM[40] = crc;
+	}
+	else
+		die("Invalid offset");
+}
diff --git a/core/hw/naomi/naomi_flashrom.h b/core/hw/naomi/naomi_flashrom.h
new file mode 100644
index 000000000..4bede04bb
--- /dev/null
+++ b/core/hw/naomi/naomi_flashrom.h
@@ -0,0 +1,25 @@
+/*
+	Created on: Apr 19, 2020
+
+	Copyright 2020 flyinghead
+
+	This file is part of flycast.
+
+    flycast is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    flycast is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with flycast.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include "types.h"
+
+void write_naomi_flash(u32 addr, u8 value);
+void write_naomi_eeprom(u32 offset, u8 value);
diff --git a/core/hw/naomi/naomi_roms.h b/core/hw/naomi/naomi_roms.h
index 003935e02..f3db5e3dd 100644
--- a/core/hw/naomi/naomi_roms.h
+++ b/core/hw/naomi/naomi_roms.h
@@ -3291,7 +3291,10 @@ Games[] =
             { "mpr-23339.ic16s",0x8000000, 0x0800000 },
             { "mpr-23340.ic17s",0x8800000, 0x0800000 },
             { NULL, 0, 0 },
-        }
+        },
+		NULL,
+		NULL,
+		slashout_eeprom_dump
     },
     // Sega Marine Fishing
     {
@@ -3828,7 +3831,8 @@ Games[] =
             { NULL, 0, 0 },
         },
         NULL,
-        &vonot_inputs
+        &vonot_inputs,
+		vonot_eeprom_dump
     },
     // Virtua Striker 2 Ver. 2000 (JPN, USA, EXP, KOR, AUS) (Rev C)
     {
@@ -3942,6 +3946,7 @@ Games[] =
         },
 		NULL,
 		&wrungp_inputs,
+		wrungp_eeprom_dump
     },
     // Wave Runner GP (USA, Rev A)
     {
@@ -3972,6 +3977,7 @@ Games[] =
         },
 		NULL,
 		&wrungp_inputs,
+		wrungp_eeprom_dump
     },
     // World Kicks (WK2 Ver. A)
     {
@@ -4938,10 +4944,12 @@ Games[] =
         ROT0,
         {
             { "317-5069-com.pic", 0, 0x4000 },
-            { "gundmgd-default-eeprom.bin", 0, 0x80,  0x0000000, Eeprom },
+            //{ "gundmgd-default-eeprom.bin", 0, 0x80,  0x0000000, Eeprom },
             { NULL, 0, 0 },
         },
         "gdl-0001",
+		NULL,
+		gundmct_eeprom_dump
     },
     // Mobile Suit Gundam: Federation Vs. Zeon DX (USA, Japan) (GDL-0006)
     {
@@ -4956,10 +4964,12 @@ Games[] =
         ROT0,
         {
             { "317-5079-com.pic", 0, 0x4000 },
-            { "gundmxgd-default-eeprom.bin", 0, 0x80,  0x0000000, Eeprom },
+            //{ "gundmxgd-default-eeprom.bin", 0, 0x80,  0x0000000, Eeprom },
             { NULL, 0, 0 },
         },
         "gdl-0006",
+		NULL,
+		gundmxgd_eeprom_dump
     },
     // Ikaruga (GDL-0010)
     {
@@ -5485,6 +5495,8 @@ Games[] =
             { NULL, 0, 0 },
         },
         "gds-0004",
+		NULL,
+		slashout_eeprom_dump
     },
     // Spikers Battle (GDS-0005)
     {
@@ -5502,6 +5514,8 @@ Games[] =
             { NULL, 0, 0 },
         },
         "gds-0005",
+		NULL,
+		spkrbtl_eeprom_dump
     },
     // Sports Jam (GDS-0003)
     {
diff --git a/core/hw/naomi/naomi_roms_eeprom.h b/core/hw/naomi/naomi_roms_eeprom.h
index 8941e656e..01cf39b71 100644
--- a/core/hw/naomi/naomi_roms_eeprom.h
+++ b/core/hw/naomi/naomi_roms_eeprom.h
@@ -89,12 +89,23 @@ static u8 alienfnt_eeprom_dump[] = {
 };
 
 static u8 gundmct_eeprom_dump[] = {
-	0xC1, 0xC1, 0x10, 0x42, 0x43, 0x56, 0x30, 0x09, 0x00, 0x0B, 0x02, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
-	0xC1, 0xC1, 0x10, 0x42, 0x43, 0x56, 0x30, 0x09, 0x00, 0x0B, 0x02, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
-	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0xbe, 0x46, 0x10, 0x42, 0x43, 0x56, 0x30, 0x18, 0x00, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0xbe, 0x46, 0x10, 0x42, 0x43, 0x56, 0x30, 0x18, 0x00, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x78, 0x1e, 0x10, 0x10, 0x78, 0x1e, 0x10, 0x10, 0x30, 0x56, 0x43, 0x42, 0x01, 0x05, 0x01, 0x01, 0x01, 0x00,
+	0x02, 0x00, 0x02, 0x02, 0x00, 0x03, 0x30, 0x56, 0x43, 0x42, 0x01, 0x05, 0x01, 0x01, 0x01, 0x00, 0x02, 0x00,
+	0x02, 0x02, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00
+};
+
+static u8 gundmxgd_eeprom_dump[] = {
+	0xd9, 0xd2, 0x10, 0x42, 0x44, 0x55, 0x30, 0x18, 0x00, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0xd9, 0xd2, 0x10, 0x42, 0x44, 0x55, 0x30, 0x18, 0x00, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x65, 0x4b, 0x20, 0x20, 0x65, 0x4b, 0x20, 0x20, 0x30, 0x55, 0x44, 0x42, 0x01, 0x05, 0x01, 0x01, 0x01, 0x00,
+	0x02, 0x00, 0x02, 0x02, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x30, 0x55, 0x44, 0x42, 0x01, 0x05, 0x01, 0x01, 0x01, 0x00, 0x02, 0x00, 0x02, 0x02,
+	0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00
 };
@@ -111,11 +122,11 @@ static u8 kick4csh_eeprom_dump[] = {
 };
 
 static u8 hmgeo_eeprom_dump[] = {
-	0xCA, 0xFB, 0x10, 0x42, 0x43, 0x57, 0x30, 0x09, 0x10, 0x00, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
-	0xCA, 0xFB, 0x10, 0x42, 0x43, 0x57, 0x30, 0x09, 0x10, 0x00, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
-	0xED, 0x2A, 0x20, 0x20, 0xED, 0x2A, 0x20, 0x20, 0x06, 0x06, 0x01, 0x20, 0x03, 0x00, 0x00, 0x01, 0x00, 0x01,
+	0x6d, 0x46, 0x10, 0x42, 0x43, 0x57, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x6d, 0x46, 0x10, 0x42, 0x43, 0x57, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x69, 0x61, 0x20, 0x20, 0x69, 0x61, 0x20, 0x20, 0x06, 0x06, 0x01, 0x20, 0x01, 0x00, 0x00, 0x01, 0x00, 0x01,
 	0x03, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-	0x00, 0x00, 0x00, 0x00, 0x06, 0x06, 0x01, 0x20, 0x03, 0x00, 0x00, 0x01, 0x00, 0x01, 0x03, 0x03, 0x01, 0x01,
+	0x00, 0x00, 0x00, 0x00, 0x06, 0x06, 0x01, 0x20, 0x01, 0x00, 0x00, 0x01, 0x00, 0x01, 0x03, 0x03, 0x01, 0x01,
 	0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00
@@ -143,4 +154,48 @@ static u8 ringout_eeprom_dump[] = {
 	0x00, 0x00
 };
 
+static u8 slashout_eeprom_dump[] = {
+	0x7f, 0x5d, 0x10, 0x42, 0x43, 0x45, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x7f, 0x5d, 0x10, 0x42, 0x43, 0x45, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0xc6, 0xa4, 0x08, 0x08, 0xc6, 0xa4, 0x08, 0x08, 0x42, 0x43, 0x45, 0x30, 0x00, 0x02, 0x00, 0x00, 0x42, 0x43,
+	0x45, 0x30, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00
+};
+
+static u8 spkrbtl_eeprom_dump[] = {
+	0x42, 0xec, 0x10, 0x42, 0x43, 0x5a, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x42, 0xec, 0x10, 0x42, 0x43, 0x5a, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0xd5, 0x9f, 0x10, 0x10, 0xd5, 0x9f, 0x10, 0x10, 0x42, 0x43, 0x5a, 0x30, 0x00, 0x02, 0x02, 0x02, 0x00, 0x00,
+	0xc0, 0x12, 0x2c, 0x01, 0x01, 0x00, 0x42, 0x43, 0x5a, 0x30, 0x00, 0x02, 0x02, 0x02, 0x00, 0x00, 0xc0, 0x12,
+	0x2c, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00
+};
+
+static u8 vonot_eeprom_dump[] = {
+	0x93, 0xac, 0x10, 0x42, 0x42, 0x56, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x93, 0xac, 0x10, 0x42, 0x42, 0x56, 0x30, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0xb7, 0x0a, 0x1c, 0x1c, 0xb7, 0x0a, 0x1c, 0x1c, 0x66, 0x05, 0x4f, 0x56, 0x06, 0x00, 0x08, 0x00, 0x02, 0x02,
+	0x02, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x01, 0x01,
+	0x66, 0x05, 0x4f, 0x56, 0x06, 0x00, 0x08, 0x00, 0x02, 0x02, 0x02, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x03, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00
+};
+
+static u8 wrungp_eeprom_dump[] = {
+	0x53, 0x45, 0x10, 0x42, 0x44, 0x44, 0x34, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x53, 0x45, 0x10, 0x42, 0x44, 0x44, 0x34, 0x18, 0x10, 0x1a, 0x01, 0x01, 0x01, 0x00, 0x11, 0x11, 0x11, 0x11,
+	0x89, 0x55, 0x22, 0x24, 0x89, 0x55, 0x22, 0x24, 0x42, 0x44, 0x44, 0x34, 0x01, 0x01, 0x01, 0x00, 0x01, 0x02,
+	0x80, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x80, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00,
+	0x81, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x42, 0x44, 0x44, 0x34, 0x01, 0x01, 0x01, 0x00, 0x01, 0x02,
+	0x80, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x80, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00,
+	0x81, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00
+};
+
 #endif /* CORE_HW_NAOMI_NAOMI_ROMS_EEPROM_H_ */
diff --git a/core/network/naomi_network.cpp b/core/network/naomi_network.cpp
index 81d1fdf2c..908689659 100644
--- a/core/network/naomi_network.cpp
+++ b/core/network/naomi_network.cpp
@@ -24,6 +24,8 @@
 #include <chrono>
 #include <thread>
 #include "rend/gui.h"
+#include "hw/naomi/naomi_cart.h"
+#include "hw/naomi/naomi_flashrom.h"
 
 sock_t NaomiNetwork::createAndBind(int protocol)
 {
@@ -55,6 +57,8 @@ sock_t NaomiNetwork::createAndBind(int protocol)
 
 bool NaomiNetwork::init()
 {
+	if (!settings.network.Enable)
+		return false;
 #ifdef _WIN32
 	WSADATA wsaData;
 	if (WSAStartup(MAKEWORD(2, 0), &wsaData) != 0)
@@ -474,3 +478,70 @@ void NaomiNetwork::terminate()
 		server_sock = INVALID_SOCKET;
 	}
 }
+
+// Sets the game network config using MIE eeprom or bbsram:
+// Node -1 disables network
+// Node 0 is master, nodes 1+ are slave
+void SetNaomiNetworkConfig(int node)
+{
+	if (!strcmp("ALIEN FRONT", naomi_game_id))
+	{
+		// no way to disable the network
+		write_naomi_eeprom(0x3f, node == 0 ? 0 : 1);
+	}
+	else if (!strcmp("MOBILE SUIT GUNDAM JAPAN", naomi_game_id) // gundmct
+			|| !strcmp("MOBILE SUIT GUNDAM DELUXE JAPAN", naomi_game_id)) // gundmxgd
+	{
+		write_naomi_eeprom(0x38, node == -1 ? 2
+				: node == 0 ? 0 : 1);
+	}
+	else if (!strcmp(" BIOHAZARD  GUN SURVIVOR2", naomi_game_id))
+	{
+		// FIXME need default flash
+		write_naomi_flash(0x21c, node == 0 ? 0 : 1);	// CPU ID - 1
+		write_naomi_flash(0x22a, node == -1 ? 0 : 1);	// comm link on
+	}
+	else if (!strcmp("HEAVY METAL JAPAN", naomi_game_id))
+	{
+		write_naomi_eeprom(0x31, node == -1 ? 0 : node == 0 ? 1 : 2);
+	}
+	else if (!strcmp("OUTTRIGGER     JAPAN", naomi_game_id))
+	{
+		// FIXME need default flash
+		write_naomi_flash(0x21a, node == -1 ? 0 : 1);	// network on
+		write_naomi_flash(0x21b, node);					// node id
+	}
+	else if (!strcmp("SLASHOUT JAPAN VERSION", naomi_game_id))
+	{
+		write_naomi_eeprom(0x30, node == -1 ? 0
+				: node == 0 ? 1 : 2);
+	}
+	else if (!strcmp("SPAWN JAPAN", naomi_game_id))
+	{
+		write_naomi_eeprom(0x44, node == -1 ? 0 : 1);	// network on
+		write_naomi_eeprom(0x30, node <= 0 ? 1 : 2);	// node id
+	}
+	else if (!strcmp("SPIKERS BATTLE JAPAN VERSION", naomi_game_id))
+	{
+		write_naomi_eeprom(0x30, node == -1 ? 0
+				: node == 0 ? 1 : 2);
+	}
+	else if (!strcmp("VIRTUAL-ON ORATORIO TANGRAM", naomi_game_id))
+	{
+		write_naomi_eeprom(0x45, node == -1 ? 3
+				: node == 0 ? 0 : 1);
+		write_naomi_eeprom(0x47, node == 0 ? 0 : 1);
+	}
+	else if (!strcmp("WAVE RUNNER GP", naomi_game_id))
+	{
+		write_naomi_eeprom(0x33, node);
+		write_naomi_eeprom(0x35, node == -1 ? 2
+				: node == 0 ? 0 : 1);
+	}
+	else if (!strcmp("WORLD KICKS", naomi_game_id))
+	{
+		// FIXME need default flash
+		write_naomi_flash(0x224, node == -1 ? 0 : 1);	// network on
+		write_naomi_flash(0x220, node == 0 ? 0 : 1);	// node id
+	}
+}
diff --git a/core/network/naomi_network.h b/core/network/naomi_network.h
index e219204b4..f24c609f3 100644
--- a/core/network/naomi_network.h
+++ b/core/network/naomi_network.h
@@ -73,3 +73,5 @@ private:
 
 	static const uint16_t SERVER_PORT = 37391;
 };
+
+void SetNaomiNetworkConfig(int node);
diff --git a/core/nullDC.cpp b/core/nullDC.cpp
index 8ac2f1aa3..9f7bd5481 100755
--- a/core/nullDC.cpp
+++ b/core/nullDC.cpp
@@ -28,6 +28,7 @@
 #include "cheats.h"
 #include "rend/CustomTexture.h"
 #include "hw/maple/maple_devs.h"
+#include "network/naomi_network.h"
 
 void FlushCache();
 void LoadCustom();
@@ -635,7 +636,11 @@ void dc_start_game(const char *path)
 		naomi_cart_LoadRom(path);
 		LoadCustom();
 		if (settings.platform.system == DC_PLATFORM_NAOMI)
+		{
 			mcfg_CreateNAOMIJamma();
+			SetNaomiNetworkConfig(settings.network.Enable ? settings.network.ActAsServer ? 0 : 1	// FIXME more than 2 nodes
+					: -1);
+		}
 		else if (settings.platform.system == DC_PLATFORM_ATOMISWAVE)
 			mcfg_CreateAtomisWaveControllers();
 	}
@@ -798,6 +803,7 @@ void InitSettings()
 		settings.input.maple_expansion_devices[i][0] = i == 0 ? MDT_SegaVMU : MDT_None;
 		settings.input.maple_expansion_devices[i][1] = i == 0 ? MDT_SegaVMU : MDT_None;
 	}
+	settings.network.Enable = false;
 	settings.network.ActAsServer = false;
 	settings.network.dns = "46.101.91.123";		// Dreamcast Live DNS
 	settings.network.server = "";
@@ -904,6 +910,7 @@ void LoadSettings(bool game_specific)
 		sprintf(device_name, "device%d.2", i + 1);
 		settings.input.maple_expansion_devices[i][1] = (MapleDeviceType)cfgLoadInt(input_section, device_name, settings.input.maple_expansion_devices[i][1]);
 	}
+	settings.network.Enable = cfgLoadBool("network", "Enable", settings.network.Enable);
 	settings.network.ActAsServer = cfgLoadBool("network", "ActAsServer", settings.network.ActAsServer);
 	settings.network.dns = cfgLoadStr("network", "DNS", settings.network.dns.c_str());
 	settings.network.server = cfgLoadStr("network", "server", settings.network.server.c_str());
@@ -1064,6 +1071,7 @@ void SaveSettings()
 	}
 	cfgSaveStr("config", "Dreamcast.ContentPath", paths.c_str());
 	cfgSaveBool("config", "Dreamcast.HideLegacyNaomiRoms", settings.dreamcast.HideLegacyNaomiRoms);
+	cfgSaveBool("network", "Enable", settings.network.Enable);
 	cfgSaveBool("network", "ActAsServer", settings.network.ActAsServer);
 	cfgSaveStr("network", "DNS", settings.network.dns.c_str());
 	cfgSaveStr("network", "server", settings.network.server.c_str());
diff --git a/core/rend/gui.cpp b/core/rend/gui.cpp
index 5058a21b3..f587b0639 100644
--- a/core/rend/gui.cpp
+++ b/core/rend/gui.cpp
@@ -1304,15 +1304,21 @@ static void gui_display_settings()
 		    }
 		    if (ImGui::CollapsingHeader("Network", ImGuiTreeNodeFlags_DefaultOpen))
 		    {
-		    	ImGui::Checkbox("Act as Server", &settings.network.ActAsServer);
-	            ImGui::SameLine();
-	            ShowHelpMarker("Create a local server for Naomi network games");
-	            char server_name[256];
-	            strcpy(server_name, settings.network.server.c_str());
-		    	ImGui::InputText("Server", server_name, sizeof(server_name), ImGuiInputTextFlags_CharsNoBlank, nullptr, nullptr);
-	            ImGui::SameLine();
-	            ShowHelpMarker("The server to connect to. Leave blank to find a server automatically");
-		    	settings.network.server = server_name;
+		    	ImGui::Checkbox("Enable", &settings.network.Enable);
+				ImGui::SameLine();
+				ShowHelpMarker("Enable networking for supported Naomi games");
+		    	if (settings.network.Enable)
+		    	{
+					ImGui::Checkbox("Act as Server", &settings.network.ActAsServer);
+					ImGui::SameLine();
+					ShowHelpMarker("Create a local server for Naomi network games");
+					char server_name[256];
+					strcpy(server_name, settings.network.server.c_str());
+					ImGui::InputText("Server", server_name, sizeof(server_name), ImGuiInputTextFlags_CharsNoBlank, nullptr, nullptr);
+					ImGui::SameLine();
+					ShowHelpMarker("The server to connect to. Leave blank to find a server automatically");
+					settings.network.server = server_name;
+		    	}
 		    }
 		    if (ImGui::CollapsingHeader("Other", ImGuiTreeNodeFlags_DefaultOpen))
 		    {
diff --git a/core/serialize.cpp b/core/serialize.cpp
index 010de1931..12c5f50fd 100644
--- a/core/serialize.cpp
+++ b/core/serialize.cpp
@@ -98,7 +98,7 @@ extern GD_StatusT GDStatus;
 extern ByteCount_t ByteCount ;
 
 //./core/hw/maple/maple_devs.o
-extern char EEPROM[0x100];
+extern u8 EEPROM[0x100];
 extern bool EEPROM_loaded;
 
 //./core/hw/maple/maple_if.o
diff --git a/core/types.h b/core/types.h
index 698659028..6ba597aa8 100644
--- a/core/types.h
+++ b/core/types.h
@@ -534,6 +534,7 @@ struct settings_t
 	} input;
 
 	struct {
+		bool Enable;
 		bool ActAsServer;
 		std::string dns;
 		std::string server;
diff --git a/shell/apple/emulator-osx/reicast-osx.xcodeproj/project.pbxproj b/shell/apple/emulator-osx/reicast-osx.xcodeproj/project.pbxproj
index 6c72d2fa8..c28b68b53 100644
--- a/shell/apple/emulator-osx/reicast-osx.xcodeproj/project.pbxproj
+++ b/shell/apple/emulator-osx/reicast-osx.xcodeproj/project.pbxproj
@@ -250,6 +250,7 @@
 		AE8C274321122E2500D4D8F4 /* xbrz.cpp in Sources */ = {isa = PBXBuildFile; fileRef = AE8C273D21122E2500D4D8F4 /* xbrz.cpp */; };
 		AE90679B235B6F6400CE473C /* gl_context.cpp in Sources */ = {isa = PBXBuildFile; fileRef = AE90679A235B6F6400CE473C /* gl_context.cpp */; };
 		AE90679D235DF80400CE473C /* osd.cpp in Sources */ = {isa = PBXBuildFile; fileRef = AE90679C235DF80400CE473C /* osd.cpp */; };
+		AEA94931244CDF50001134C7 /* naomi_flashrom.cpp in Sources */ = {isa = PBXBuildFile; fileRef = AEA9492F244CDF50001134C7 /* naomi_flashrom.cpp */; };
 		AED73BAE22FC0E9600ECDB64 /* README.md in Resources */ = {isa = PBXBuildFile; fileRef = AED73BAD22FC0E9600ECDB64 /* README.md */; };
 		AED73DC42303E19200ECDB64 /* sdl.cpp in Sources */ = {isa = PBXBuildFile; fileRef = AED73DC02303E19100ECDB64 /* sdl.cpp */; };
 		AED73DCC233ACC9800ECDB64 /* cheats.cpp in Sources */ = {isa = PBXBuildFile; fileRef = AED73DCB233ACC9800ECDB64 /* cheats.cpp */; };
@@ -815,6 +816,8 @@
 		AE8C274021122E2500D4D8F4 /* xbrz_tools.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = xbrz_tools.h; sourceTree = "<group>"; };
 		AE90679A235B6F6400CE473C /* gl_context.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = gl_context.cpp; sourceTree = "<group>"; };
 		AE90679C235DF80400CE473C /* osd.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = osd.cpp; sourceTree = "<group>"; };
+		AEA9492F244CDF50001134C7 /* naomi_flashrom.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = naomi_flashrom.cpp; sourceTree = "<group>"; };
+		AEA94930244CDF50001134C7 /* naomi_roms_eeprom.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = naomi_roms_eeprom.h; sourceTree = "<group>"; };
 		AED73BAD22FC0E9600ECDB64 /* README.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; name = README.md; path = ../../../core/README.md; sourceTree = "<group>"; };
 		AED73DC02303E19100ECDB64 /* sdl.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = sdl.cpp; sourceTree = "<group>"; };
 		AED73DC12303E19100ECDB64 /* sdl.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = sdl.h; sourceTree = "<group>"; };
@@ -2070,8 +2073,10 @@
 				AE2A2D5021D6846F004B308D /* m1cartridge.h */,
 				AE2A2D5621D68470004B308D /* m4cartridge.cpp */,
 				AE2A2D5421D68470004B308D /* m4cartridge.h */,
+				AEA9492F244CDF50001134C7 /* naomi_flashrom.cpp */,
 				AE7BCB6C24460910007285F8 /* naomi_m3comm.cpp */,
 				AE7BCB6D24460910007285F8 /* naomi_m3comm.h */,
+				AEA94930244CDF50001134C7 /* naomi_roms_eeprom.h */,
 				AE2A2D5821D68470004B308D /* naomi_roms_input.h */,
 				AE2A2D5521D68470004B308D /* naomi_roms.h */,
 				AE80EDB92157D4E600F7800F /* naomi.cpp */,
@@ -2754,6 +2759,7 @@
 				8491687F1B782B2D00F3F2B4 /* ini.cpp in Sources */,
 				84B7BF341B72720200F9733F /* maple_cfg.cpp in Sources */,
 				AE649C2D218C553A00EF4A81 /* LzmaDec.c in Sources */,
+				AEA94931244CDF50001134C7 /* naomi_flashrom.cpp in Sources */,
 				AE649C3D218C555600EF4A81 /* chd.c in Sources */,
 				AED73E762348E45000ECDB64 /* Scan.cpp in Sources */,
 				AE649C25218C553A00EF4A81 /* Bra.c in Sources */,
@@ -2990,7 +2996,7 @@
 					"USE_SDL=1",
 					XXH_INLINE_ALL,
 					VK_USE_PLATFORM_MACOS_MVK,
-					Z_HAVE_UNISTD_H
+					Z_HAVE_UNISTD_H,
 				);
 				GCC_SYMBOLS_PRIVATE_EXTERN = NO;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
@@ -3045,7 +3051,7 @@
 					"USE_SDL=1",
 					XXH_INLINE_ALL,
 					VK_USE_PLATFORM_MACOS_MVK,
-					Z_HAVE_UNISTD_H
+					Z_HAVE_UNISTD_H,
 				);
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
 				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;