diff --git a/BOOT/ENVIRON/INC/bootmgr.h b/BOOT/ENVIRON/INC/bootmgr.h
index 5e79bb6..6acdf09 100644
--- a/BOOT/ENVIRON/INC/bootmgr.h
+++ b/BOOT/ENVIRON/INC/bootmgr.h
@@ -135,21 +135,27 @@ typedef struct {
 //
 #define MEMORY_ATTRIBUTE_RUNTIME 0x1000000
 
-typedef enum {
-    MEMORY_TYPE_BOOT_APPLICATION = 0xD0000002,
-    MEMORY_TYPE_FREE = 0xF0000001,
-    MEMORY_TYPE_UNUSABLE = 0xF0000002,
-    MEMORY_TYPE_RESERVED = 0xF0000003,
-    MEMORY_TYPE_BOOT_SERVICES = 0xF0000004,
-    MEMORY_TYPE_RUNTIME_SERVICES_CODE = 0xF0000006,
-    MEMORY_TYPE_PERSISTENT = 0xF0000007,
-    MEMORY_TYPE_ACPI_RECLAIM = 0xF0000008,
-    MEMORY_TYPE_ACPI_NVS = 0xF0000009,
-    MEMORY_TYPE_MMIO = 0xF000000A,
-    MEMORY_TYPE_MMIO_PORT_SPACE = 0xF000000B,
-    MEMORY_TYPE_PAL_CODE = 0xF000000C,
-    MEMORY_TYPE_RUNTIME_SERVICES_DATA = 0xF000000E
-} MEMORY_TYPE;
+#define MEMORY_CLASS_APPLICATION 0xD
+#define MEMORY_CLASS_LIBRARY     0xE
+#define MEMORY_CLASS_SYSTEM      0xF
+
+#define MEMORY_TYPE_BOOT_APPLICATION      0xD0000002
+#define MEMORY_TYPE_BOOT_APPLICATION_2    0xD0000013
+#define MEMORY_TYPE_FREE                  0xF0000001
+#define MEMORY_TYPE_UNUSABLE              0xF0000002
+#define MEMORY_TYPE_RESERVED              0xF0000003
+#define MEMORY_TYPE_BOOT_SERVICES         0xF0000004
+#define MEMORY_TYPE_FREE_ZEROED           0xF0000005
+#define MEMORY_TYPE_RUNTIME_SERVICES_CODE 0xF0000006
+#define MEMORY_TYPE_PERSISTENT            0xF0000007
+#define MEMORY_TYPE_ACPI_RECLAIM          0xF0000008
+#define MEMORY_TYPE_ACPI_NVS              0xF0000009
+#define MEMORY_TYPE_MMIO                  0xF000000A
+#define MEMORY_TYPE_MMIO_PORT_SPACE       0xF000000B
+#define MEMORY_TYPE_PAL_CODE              0xF000000C
+#define MEMORY_TYPE_RUNTIME_SERVICES_DATA 0xF000000E
+
+typedef ULONG MEMORY_TYPE;
 
 typedef struct {
     LIST_ENTRY ListEntry;
diff --git a/BOOT/ENVIRON/LIB/MM/mmmd.c b/BOOT/ENVIRON/LIB/MM/mmmd.c
index ffdf89f..1a85251 100644
--- a/BOOT/ENVIRON/LIB/MM/mmmd.c
+++ b/BOOT/ENVIRON/LIB/MM/mmmd.c
@@ -27,10 +27,27 @@ ULONG MmGlobalMemoryDescriptorCount, MmGlobalMemoryDescriptorsUsed;
 PMEMORY_DESCRIPTOR MmDynamicMemoryDescriptors;
 ULONG MmDynamicMemoryDescriptorCount, MmDynamicMemoryDescriptorsUsed;
 
+MEMORY_TYPE MmPlatformMemoryTypePrecedence[] = {
+    MEMORY_TYPE_RESERVED,
+    MEMORY_TYPE_UNUSABLE,
+    MEMORY_TYPE_MMIO,
+    MEMORY_TYPE_MMIO_PORT_SPACE,
+    MEMORY_TYPE_PAL_CODE,
+    MEMORY_TYPE_RUNTIME_SERVICES_CODE,
+    MEMORY_TYPE_RUNTIME_SERVICES_DATA,
+    MEMORY_TYPE_ACPI_NVS,
+    MEMORY_TYPE_ACPI_RECLAIM,
+    MEMORY_TYPE_PERSISTENT,
+    MEMORY_TYPE_BOOT_APPLICATION_2,
+    MEMORY_TYPE_BOOT_SERVICES,
+    MEMORY_TYPE_FREE,
+    MEMORY_TYPE_FREE_ZEROED
+};
+
 BOOLEAN
 MmMdpHasPrecedence (
-    IN MEMORY_TYPE A,
-    IN MEMORY_TYPE B
+    IN MEMORY_TYPE TypeA,
+    IN MEMORY_TYPE TypeB
     )
 
 /*++
@@ -41,52 +58,71 @@ Routine Description:
 
 Arguments:
 
-    A - memory type A.
+    TypeA - memory type A.
 
-    B - memory type B.
+    TypeB - memory type B.
 
 Return Value:
 
-    TRUE if A has precedence over B, or if neither has precedence.
-    FALSE if B has precedence over A.
+    TRUE if TypeA has precedence over TypeB, or if neither has precedence.
+    FALSE if TypeB has precedence over TypeA.
 
 --*/
 
 {
     ULONG ClassA, ClassB;
+    ULONG IndexA, IndexB;
 
-    ClassA = A >> 28;
-    ClassB = B >> 28;
-
-    if (B == MEMORY_TYPE_FREE) {
+    if (TypeB == MEMORY_TYPE_FREE_ZEROED) {
         return TRUE;
-    }
-
-    if (A == MEMORY_TYPE_FREE) {
+    } else if (TypeA == MEMORY_TYPE_FREE_ZEROED) {
+        return FALSE;
+    } else if (TypeB == MEMORY_TYPE_FREE) {
+        return TRUE;
+    } else if (TypeA == MEMORY_TYPE_FREE) {
         return FALSE;
     }
 
-    if (ClassA > 0x0F) {
+    ClassA = TypeA >> 28;
+    ClassB = TypeB >> 28;
+    if (ClassA != MEMORY_CLASS_APPLICATION
+        && ClassA != MEMORY_CLASS_LIBRARY
+        && ClassA != MEMORY_CLASS_SYSTEM) {
         return TRUE;
-    }
-
-    if (ClassB > 0x0F) {
+    } else if (ClassB != MEMORY_CLASS_APPLICATION
+        && ClassB != MEMORY_CLASS_LIBRARY
+        && ClassB != MEMORY_CLASS_SYSTEM) {
         return FALSE;
     }
 
-    if (ClassA != 0x0F) {
-        return (ClassB != 0x0F && (ClassA == 0x0D || ClassB != 0x0D)) ? TRUE:FALSE;
-    }
-
-    if (ClassB != 0x0F) {
+    if (ClassA != MEMORY_CLASS_SYSTEM) {
+        return (ClassB != MEMORY_CLASS_SYSTEM
+                && (ClassA == MEMORY_CLASS_APPLICATION
+                    || ClassB != MEMORY_CLASS_APPLICATION)) ? TRUE:FALSE;
+    } else if (ClassB != MEMORY_CLASS_SYSTEM) {
         return TRUE;
     }
 
-    //
-    // TODO: Implement the rest of this routine.
-    //
-    ConsolePrint(L"MmMdpHasPrecedence() is incomplete\r\n");
+    for (IndexA = 0;
+         IndexA < sizeof(MmPlatformMemoryTypePrecedence) / sizeof(MmPlatformMemoryTypePrecedence[0]);
+         IndexA++) {
+        if (TypeA == MmPlatformMemoryTypePrecedence[IndexA]) {
+            goto CheckTypeBPrecedence;
+        }
+    }
+
     return TRUE;
+
+CheckTypeBPrecedence:
+    for (IndexB = 0;
+         IndexB < sizeof(MmPlatformMemoryTypePrecedence) / sizeof(MmPlatformMemoryTypePrecedence[0]);
+         IndexB++) {
+        if (TypeB == MmPlatformMemoryTypePrecedence[IndexB]) {
+            return IndexA <= IndexB ? TRUE:FALSE;
+        }
+    }
+
+    return FALSE;
 }
 
 BOOLEAN