diff --git a/reactos/hal/halx86/generic/bios.c b/reactos/hal/halx86/generic/bios.c
index 00bcbda41f8..ca79a65e84d 100644
--- a/reactos/hal/halx86/generic/bios.c
+++ b/reactos/hal/halx86/generic/bios.c
@@ -1,9 +1,9 @@
 /*
- * PROJECT:         ReactOS HAL
- * LICENSE:         GPL - See COPYING in the top level directory
- * FILE:            hal/halx86/generic/bios.c
+ * PROJECT:         ReactOS Hardware Abstraction Layer (HAL)
+ * LICENSE:         BSD - See COPYING.ARM in the top level directory
+ * FILE:            halx86/generic/bios.c
  * PURPOSE:         BIOS Access Routines
- * PROGRAMMERS:     Alex Ionescu (alex.ionescu@reactos.org)
+ * PROGRAMMERS:     ReactOS Portable Systems Group
  */
 
 /* INCLUDES *******************************************************************/
@@ -14,14 +14,15 @@
 
 /* GLOBALS ********************************************************************/
 
-UCHAR HalpIopmSaveBuffer[0x2000];
 ULONG HalpSavedPfn;
 HARDWARE_PTE HalpSavedPte;
 ULONG HalpGpfHandler;
 ULONG HalpBopHandler;
-USHORT HalpSavedIopmBase;
-PUCHAR HalpSavedIoMap;
 ULONG HalpSavedEsp0;
+USHORT HalpSavedIopmBase;
+PUSHORT HalpSavedIoMap;
+USHORT HalpSavedIoMapData[32][2];
+ULONG HalpSavedIoMapEntries;
 
 #define GetPdeAddress(x) (PHARDWARE_PTE)(((((ULONG_PTR)(x)) >> 22) << 2) + 0xC0300000)
 #define GetPteAddress(x) (PHARDWARE_PTE)(((((ULONG_PTR)(x)) >> 12) << 2) + 0xC0000000)
@@ -30,27 +31,61 @@ ULONG HalpSavedEsp0;
 
 VOID
 NTAPI
-HalpStoreAndClearIopm(IN PUCHAR IoMap)
+HalpStoreAndClearIopm(VOID)
 {
-    ULONG i;
-    
-    /* Backup the old I/O Map */
-    RtlCopyMemory(HalpIopmSaveBuffer, IoMap, 0x2000);
+    ULONG i, j;
+    PUSHORT Entry = HalpSavedIoMap;
 
-    /* Erase the current one */
-    for (i = 0; i < 0x2000; i++) IoMap[i] = 0;
-    for (i = 0x2000; i < 0x2004; i++) IoMap[i] = 0xFF;
+    //
+    // Loop the I/O Map
+    //
+    for (i = j = 0; i < (IOPM_SIZE) / 2; i++)
+    {
+        //
+        // Check for non-FFFF entry
+        //
+        if (*Entry != 0xFFFF)
+        {
+            //
+            // Save it
+            //
+            ASSERT(j < 32);
+            HalpSavedIoMapData[j][0] = i;
+            HalpSavedIoMapData[j][1] = *Entry;
+        }
+
+        //
+        // Clear it
+        //
+        *Entry++ = 0;
+    }
+
+    //
+    // Terminate it
+    //
+    while (i++ < (IOPM_FULL_SIZE / 2)) *Entry++ = 0xFFFF;
+
+    //
+    // Return the entries we saved
+    //
+    HalpSavedIoMapEntries = j;
 }
 
 VOID
 NTAPI
-HalpRestoreIopm(IN PUCHAR IoMap)
+HalpRestoreIopm(VOID)
 {
-    ULONG i;
+    ULONG i = HalpSavedIoMapEntries;
 
-    /* Restore the backed up copy, and initialize it */
-    RtlCopyMemory(IoMap, HalpIopmSaveBuffer, 0x2000);
-    for (i = 0x2000; i < 0x2004; i++) IoMap[i] = 0xFF;
+    //
+    // Set default state
+    //
+    RtlFillMemory(HalpSavedIoMap, 0xFF, IOPM_FULL_SIZE);
+
+    //
+    // Restore the backed up copy, and initialize it
+    //
+    while (i--) HalpSavedIoMap[HalpSavedIoMapData[i][0]] = HalpSavedIoMapData[i][1];
 }
 
 VOID
@@ -134,8 +169,8 @@ NTAPI
 HalpSetupRealModeIoPermissionsAndTask(VOID)
 {
     /* Save a copy of the I/O Map and delete it */
-    HalpSavedIoMap = (PUCHAR)&(KeGetPcr()->TSS->IoMaps[0]);
-    HalpStoreAndClearIopm(HalpSavedIoMap);
+    HalpSavedIoMap = (PUSHORT)&(KeGetPcr()->TSS->IoMaps[0]);
+    HalpStoreAndClearIopm();
     
     /* Save the IOPM and switch to the real-mode one */
     HalpSavedIopmBase = KeGetPcr()->TSS->IoMapBase;
@@ -166,7 +201,7 @@ HalpRestoreIoPermissionsAndTask(VOID)
     KeGetPcr()->TSS->Esp0 = HalpSavedEsp0;
     
     /* Restore the I/O Map */
-    HalpRestoreIopm(HalpSavedIoMap);
+    HalpRestoreIopm();
     
     /* Restore the IOPM */
     KeGetPcr()->TSS->IoMapBase = HalpSavedIopmBase;    
diff --git a/reactos/include/ndk/i386/ketypes.h b/reactos/include/ndk/i386/ketypes.h
index ad2c5a53720..4a5d4f44653 100644
--- a/reactos/include/ndk/i386/ketypes.h
+++ b/reactos/include/ndk/i386/ketypes.h
@@ -129,7 +129,11 @@ Author:
 //
 // IOPM Definitions
 //
+#define IOPM_COUNT              1
+#define IOPM_SIZE               8192
+#define IOPM_FULL_SIZE          8196
 #define IO_ACCESS_MAP_NONE      0
+#define IOPM_DIRECTION_MAP_SIZE 32
 #define IOPM_OFFSET             FIELD_OFFSET(KTSS, IoMaps[0].IoMap)
 #define KiComputeIopmOffset(MapNumber)              \
     (MapNumber == IO_ACCESS_MAP_NONE) ?             \
@@ -708,8 +712,8 @@ typedef struct _KIPCR
 //
 typedef struct _KiIoAccessMap
 {
-    UCHAR DirectionMap[32];
-    UCHAR IoMap[8196];
+    UCHAR DirectionMap[IOPM_DIRECTION_MAP_SIZE];
+    UCHAR IoMap[IOPM_FULL_SIZE];
 } KIIO_ACCESS_MAP;
 
 typedef struct _KTSS
@@ -747,8 +751,8 @@ typedef struct _KTSS
     USHORT Reserved8;
     USHORT Flags;
     USHORT IoMapBase;
-    KIIO_ACCESS_MAP IoMaps[1];
-    UCHAR IntDirectionMap[32];
+    KIIO_ACCESS_MAP IoMaps[IOPM_COUNT];
+    UCHAR IntDirectionMap[IOPM_DIRECTION_MAP_SIZE];
 } KTSS, *PKTSS;
 
 //
diff --git a/reactos/ntoskrnl/ke/i386/cpu.c b/reactos/ntoskrnl/ke/i386/cpu.c
index ad6d11293b5..760b9fb6c3c 100644
--- a/reactos/ntoskrnl/ke/i386/cpu.c
+++ b/reactos/ntoskrnl/ke/i386/cpu.c
@@ -582,11 +582,12 @@ KiInitializeTSS2(IN PKTSS Tss,
     }
 
     /* Now clear the I/O Map */
-    RtlFillMemory(Tss->IoMaps[0].IoMap, 8096, -1);
+    ASSERT(IOPM_COUNT == 1);
+    RtlFillMemory(Tss->IoMaps[0].IoMap, IOPM_FULL_SIZE, 0xFF);
 
     /* Initialize Interrupt Direction Maps */
     p = (PUCHAR)(Tss->IoMaps[0].DirectionMap);
-    RtlZeroMemory(p, 32);
+    RtlZeroMemory(p, IOPM_DIRECTION_MAP_SIZE);
 
     /* Add DPMI support for interrupts */
     p[0] = 4;
@@ -595,7 +596,7 @@ KiInitializeTSS2(IN PKTSS Tss,
 
     /* Initialize the default Interrupt Direction Map */
     p = Tss->IntDirectionMap;
-    RtlZeroMemory(Tss->IntDirectionMap, 32);
+    RtlZeroMemory(Tss->IntDirectionMap, IOPM_DIRECTION_MAP_SIZE);
 
     /* Add DPMI support */
     p[0] = 4;