diff --git a/src/i430fx.c b/src/i430fx.c
index 5b7cf7f..4db750e 100644
--- a/src/i430fx.c
+++ b/src/i430fx.c
@@ -34,15 +34,33 @@ static void i430fx_map(uint32_t addr, uint32_t size, int state)
 void i430fx_write(int func, int addr, uint8_t val, void *priv)
 {
         if (func)
-           return;
+                return;
+
+        if (addr >= 0x10 && addr < 0x4f)
+                return;
 
         switch (addr)
         {
                 case 0x00: case 0x01: case 0x02: case 0x03:
                 case 0x08: case 0x09: case 0x0a: case 0x0b:
-                case 0x0e:
+                case 0x0c: case 0x0e:
                 return;
                 
+                case 0x04: /*Command register*/
+                val &= 0x02;
+                val |= 0x04;
+                break;
+                case 0x05:
+                val = 0;
+                break;
+                
+                case 0x06: /*Status*/
+                val = 0;
+                break;
+                case 0x07:
+                val = 0x02;
+                break;
+
                 case 0x59: /*PAM0*/
                 if ((card_i430fx[0x59] ^ val) & 0xf0)
                 {
diff --git a/src/i430lx.c b/src/i430lx.c
index 1f6a874..ebde9bc 100644
--- a/src/i430lx.c
+++ b/src/i430lx.c
@@ -36,13 +36,31 @@ void i430lx_write(int func, int addr, uint8_t val, void *priv)
         if (func)
            return;
 
+        if (addr >= 0x10 && addr < 0x4f)
+                return;
+
         switch (addr)
         {
                 case 0x00: case 0x01: case 0x02: case 0x03:
                 case 0x08: case 0x09: case 0x0a: case 0x0b:
-                case 0x0e:
+                case 0x0c: case 0x0e:
                 return;
                 
+                case 0x04: /*Command register*/
+                val &= 0x42;
+                val |= 0x04;
+                break;
+                case 0x05:
+                val &= 0x01;
+                break;
+                
+                case 0x06: /*Status*/
+                val = 0;
+                break;
+                case 0x07:
+                val = 0x02;
+                break;
+                
                 case 0x59: /*PAM0*/
                 if ((card_i430lx[0x59] ^ val) & 0xf0)
                 {
diff --git a/src/i430vx.c b/src/i430vx.c
index 5f2cb05..6b1c4bb 100644
--- a/src/i430vx.c
+++ b/src/i430vx.c
@@ -34,13 +34,32 @@ void i430vx_write(int func, int addr, uint8_t val, void *priv)
         if (func)
            return;
            
+        if (addr >= 0x10 && addr < 0x4f)
+                return;
+                
         switch (addr)
         {
                 case 0x00: case 0x01: case 0x02: case 0x03:
                 case 0x08: case 0x09: case 0x0a: case 0x0b:
-                case 0x0e:
+                case 0x0c: case 0x0e:
                 return;
                 
+                case 0x04: /*Command register*/
+                val &= 0x02;
+                val |= 0x04;
+                break;
+                case 0x05:
+                val = 0;
+                break;
+                
+                case 0x06: /*Status*/
+                val = 0;
+                break;
+                case 0x07:
+                val &= 0x80;
+                val |= 0x02;
+                break;
+                
                 case 0x59: /*PAM0*/
                 if ((card_i430vx[0x59] ^ val) & 0xf0)
                 {
diff --git a/src/piix.c b/src/piix.c
index a62ba82..1c3bc28 100644
--- a/src/piix.c
+++ b/src/piix.c
@@ -81,6 +81,9 @@ void piix_write(int func, int addr, uint8_t val, void *priv)
         }
         else
         {
+                if (addr >= 0x0f && addr < 0x4c)
+                        return;
+
                 switch (addr)
                 {
                         case 0x00: case 0x01: case 0x02: case 0x03:
@@ -343,7 +346,7 @@ void piix_init(int card, int pci_a, int pci_b, int pci_c, int pci_d)
         card_piix[0x00] = 0x86; card_piix[0x01] = 0x80; /*Intel*/
         card_piix[0x02] = 0x2e; card_piix[0x03] = 0x12; /*82371FB (PIIX)*/
         card_piix[0x04] = 0x07; card_piix[0x05] = 0x00;
-        card_piix[0x06] = 0x00; card_piix[0x07] = 0x02;
+        card_piix[0x06] = 0x80; card_piix[0x07] = 0x02;
         card_piix[0x08] = 0x00; /*A0 stepping*/
         card_piix[0x09] = 0x00; card_piix[0x0a] = 0x01; card_piix[0x0b] = 0x06;
         card_piix[0x0e] = 0x80; /*Multi-function device*/