diff --git a/base/setup/lib/utils/partlist.c b/base/setup/lib/utils/partlist.c
index 1930748ab80..19b49a6a9b0 100644
--- a/base/setup/lib/utils/partlist.c
+++ b/base/setup/lib/utils/partlist.c
@@ -748,7 +748,7 @@ IsSuperFloppy(
  * Of course no disk region should overlap at all with one another.
  */
 static
-VOID
+BOOLEAN
 InsertDiskRegion(
     IN PDISKENTRY DiskEntry,
     IN PPARTENTRY PartEntry,
@@ -801,7 +801,7 @@ InsertDiskRegion(
                      PartEntry->StartSector.QuadPart +  PartEntry->SectorCount.QuadPart - 1,
                     PartEntry2->StartSector.QuadPart,
                     PartEntry2->StartSector.QuadPart + PartEntry2->SectorCount.QuadPart - 1);
-            return;
+            return FALSE;
         }
 
         /* We have found the first region before which the new one has to be inserted */
@@ -810,6 +810,7 @@ InsertDiskRegion(
 
     /* Insert the disk region */
     InsertTailList(Entry, &PartEntry->ListEntry);
+    return TRUE;
 }
 
 static
@@ -834,6 +835,7 @@ CreateInsertBlankRegion(
     NewPartEntry->StartSector.QuadPart = StartSector;
     NewPartEntry->SectorCount.QuadPart = SectorCount;
 
+    NewPartEntry->LogicalPartition = LogicalSpace;
     NewPartEntry->IsPartitioned = FALSE;
     NewPartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
     NewPartEntry->FormatState = Unformatted;
@@ -850,69 +852,72 @@ CreateInsertBlankRegion(
 }
 
 static
-// BOOLEAN
-PPARTENTRY
+BOOLEAN
 InitializePartitionEntry(
-    IN PDISKENTRY DiskEntry,
-    IN PPARTENTRY PartEntry,
+    IN OUT PPARTENTRY PartEntry,
     IN ULONGLONG SectorCount,
     IN BOOLEAN AutoCreate)
 {
-    PPARTENTRY NewPartEntry;
+    PDISKENTRY DiskEntry = PartEntry->DiskEntry;
 
     DPRINT1("Current partition sector count: %I64u\n", PartEntry->SectorCount.QuadPart);
 
+    /* Fail if we try to initialize this partition entry with more sectors than what it actually contains */
+    if (SectorCount > PartEntry->SectorCount.QuadPart)
+        return FALSE;
+
+    /* Fail if the partition is already in use */
+    ASSERT(!PartEntry->IsPartitioned);
+
     if ((AutoCreate != FALSE) ||
         (AlignDown(PartEntry->StartSector.QuadPart + SectorCount, DiskEntry->SectorAlignment) -
                    PartEntry->StartSector.QuadPart == PartEntry->SectorCount.QuadPart))
     {
-        DPRINT1("Convert existing partition entry\n");
-
-        NewPartEntry = PartEntry;
-        NewPartEntry->AutoCreate = AutoCreate;
+        PartEntry->AutoCreate = AutoCreate;
     }
     else
     {
-        DPRINT1("Add new partition entry\n");
+        ULONGLONG StartSector;
+        ULONGLONG SectorCount2;
+        PPARTENTRY NewPartEntry;
 
-        /* Insert and initialize a new partition entry */
-        NewPartEntry = RtlAllocateHeap(ProcessHeap,
-                                       HEAP_ZERO_MEMORY,
-                                       sizeof(PARTENTRY));
+        /* Create a partition entry that represents the remaining space after the partition to be initialized */
+
+        StartSector = AlignDown(PartEntry->StartSector.QuadPart + SectorCount, DiskEntry->SectorAlignment);
+        SectorCount2 = PartEntry->StartSector.QuadPart + PartEntry->SectorCount.QuadPart - StartSector;
+
+        NewPartEntry = CreateInsertBlankRegion(DiskEntry,
+                                               PartEntry->ListEntry.Flink,
+                                               StartSector,
+                                               SectorCount2,
+                                               PartEntry->LogicalPartition);
         if (NewPartEntry == NULL)
-            return NULL;
+        {
+            DPRINT1("Failed to create a new empty region for disk space!\n");
+            return FALSE;
+        }
 
-        NewPartEntry->DiskEntry = DiskEntry;
-
-        NewPartEntry->StartSector.QuadPart = PartEntry->StartSector.QuadPart;
-        NewPartEntry->SectorCount.QuadPart = AlignDown(NewPartEntry->StartSector.QuadPart + SectorCount, DiskEntry->SectorAlignment) -
-                                             NewPartEntry->StartSector.QuadPart;
-
-        PartEntry->StartSector.QuadPart = NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart;
-        PartEntry->SectorCount.QuadPart -= (PartEntry->StartSector.QuadPart - NewPartEntry->StartSector.QuadPart);
-
-        /* Insert the new entry into the list */
-        InsertTailList(&PartEntry->ListEntry, &NewPartEntry->ListEntry);
+        /* Resize down the partition entry; its StartSector remains the same */
+        PartEntry->SectorCount.QuadPart = StartSector - PartEntry->StartSector.QuadPart;
     }
 
-    /* Create entry as 'New (Unformatted)' */
-    NewPartEntry->New = TRUE;
-    NewPartEntry->IsPartitioned = TRUE;
+    /* Convert the partition entry to 'New (Unformatted)' */
+    PartEntry->New = TRUE;
+    PartEntry->IsPartitioned = TRUE;
 
-    NewPartEntry->PartitionType = FileSystemToPartitionType(L"RAW", &NewPartEntry->StartSector, &NewPartEntry->SectorCount);
-    ASSERT(NewPartEntry->PartitionType != PARTITION_ENTRY_UNUSED);
+    PartEntry->PartitionType = FileSystemToPartitionType(L"RAW", &PartEntry->StartSector, &PartEntry->SectorCount);
+    ASSERT(PartEntry->PartitionType != PARTITION_ENTRY_UNUSED);
 
-    NewPartEntry->FormatState = Unformatted;
-    NewPartEntry->FileSystem[0] = L'\0';
-    // NewPartEntry->AutoCreate = AutoCreate;
-    NewPartEntry->BootIndicator = FALSE;
-    NewPartEntry->LogicalPartition = FALSE;
+    PartEntry->FormatState = Unformatted;
+    PartEntry->FileSystem[0] = L'\0';
+    // PartEntry->AutoCreate = AutoCreate;
+    PartEntry->BootIndicator = FALSE;
 
-    DPRINT1("First Sector : %I64u\n", NewPartEntry->StartSector.QuadPart);
-    DPRINT1("Last Sector  : %I64u\n", NewPartEntry->StartSector.QuadPart + NewPartEntry->SectorCount.QuadPart - 1);
-    DPRINT1("Total Sectors: %I64u\n", NewPartEntry->SectorCount.QuadPart);
+    DPRINT1("First Sector : %I64u\n", PartEntry->StartSector.QuadPart);
+    DPRINT1("Last Sector  : %I64u\n", PartEntry->StartSector.QuadPart + PartEntry->SectorCount.QuadPart - 1);
+    DPRINT1("Total Sectors: %I64u\n", PartEntry->SectorCount.QuadPart);
 
-    return NewPartEntry;
+    return TRUE;
 }
 
 
@@ -956,7 +961,6 @@ AddPartitionToDisk(
 
     PartEntry->BootIndicator = PartitionInfo->BootIndicator;
     PartEntry->PartitionType = PartitionInfo->PartitionType;
-    PartEntry->HiddenSectors = PartitionInfo->HiddenSectors;
 
     PartEntry->LogicalPartition = LogicalPartition;
     PartEntry->IsPartitioned = TRUE;
@@ -983,7 +987,7 @@ AddPartitionToDisk(
         ASSERT(PartitionInfo->RecognizedPartition);
         ASSERT(PartEntry->IsPartitioned && PartEntry->PartitionNumber != 0);
 
-        /* Open the volume, ignore any errors */
+        /* Try to open the volume so as to mount it */
         RtlStringCchPrintfW(PathBuffer, ARRAYSIZE(PathBuffer),
                             L"\\Device\\Harddisk%lu\\Partition%lu",
                             DiskEntry->DiskNumber,
@@ -1008,8 +1012,10 @@ AddPartitionToDisk(
             DPRINT1("NtOpenFile() failed, Status 0x%08lx\n", Status);
         }
 
-        if (/* NT_SUCCESS(Status) && */ PartitionHandle)
+        if (PartitionHandle)
         {
+            ASSERT(NT_SUCCESS(Status));
+
             /* We don't have a FS, try to guess one */
             Status = InferFileSystemByHandle(PartitionHandle,
                                              PartEntry->PartitionType,
@@ -1020,10 +1026,54 @@ AddPartitionToDisk(
         }
         if (*PartEntry->FileSystem)
         {
+            ASSERT(PartitionHandle);
+
+            /*
+             * Handle partition mounted with RawFS: it is
+             * either unformatted or has an unknown format.
+             */
             if (wcsicmp(PartEntry->FileSystem, L"RAW") == 0)
-                PartEntry->FormatState = Unformatted;
+            {
+                /*
+                 * True unformatted partitions on NT are created with their
+                 * partition type set to either one of the following values,
+                 * and are mounted with RawFS. This is done this way since we
+                 * are assured to have FAT support, which is the only FS that
+                 * uses these partition types. Therefore, having a partition
+                 * mounted with RawFS and with these partition types means that
+                 * the FAT FS was unable to mount it beforehand and thus the
+                 * partition is unformatted.
+                 * However, any partition mounted by RawFS that does NOT have
+                 * any of these partition types must be considered as having
+                 * an unknown format.
+                 */
+                if (PartEntry->PartitionType == PARTITION_FAT_12 ||
+                    PartEntry->PartitionType == PARTITION_FAT_16 ||
+                    PartEntry->PartitionType == PARTITION_HUGE   ||
+                    PartEntry->PartitionType == PARTITION_XINT13 ||
+                    PartEntry->PartitionType == PARTITION_FAT32  ||
+                    PartEntry->PartitionType == PARTITION_FAT32_XINT13)
+                {
+                    PartEntry->FormatState = Unformatted;
+                }
+                else
+                {
+                    /* Close the partition before dismounting */
+                    NtClose(PartitionHandle);
+                    PartitionHandle = NULL;
+                    /*
+                     * Dismount the partition since RawFS owns it, and set its
+                     * format to unknown (may or may not be actually formatted).
+                     */
+                    DismountVolume(PartEntry);
+                    PartEntry->FormatState = UnknownFormat;
+                    PartEntry->FileSystem[0] = L'\0';
+                }
+            }
             else
+            {
                 PartEntry->FormatState = Preformatted;
+            }
         }
         else
         {
@@ -1056,7 +1106,7 @@ AddPartitionToDisk(
     }
     else
     {
-        /* Unknown partition, hence unknown partition format (may or may not be actually formatted) */
+        /* Unknown partition, hence unknown format (may or may not be actually formatted) */
         PartEntry->FormatState = UnknownFormat;
     }
 
@@ -1195,7 +1245,6 @@ ScanForUnpartitionedDiskSpace(
                 DPRINT1("Failed to create a new empty region for full extended partition space!\n");
                 return;
             }
-            NewPartEntry->LogicalPartition = TRUE;
 
             return;
         }
@@ -1236,7 +1285,6 @@ ScanForUnpartitionedDiskSpace(
                         DPRINT1("Failed to create a new empty region for extended partition space!\n");
                         return;
                     }
-                    NewPartEntry->LogicalPartition = TRUE;
                 }
 
                 LastStartSector = PartEntry->StartSector.QuadPart;
@@ -1269,7 +1317,6 @@ ScanForUnpartitionedDiskSpace(
                     DPRINT1("Failed to create a new empty region for extended partition space!\n");
                     return;
                 }
-                NewPartEntry->LogicalPartition = TRUE;
             }
         }
     }
@@ -1846,9 +1893,9 @@ CreatePartitionList(VOID)
     ULONG ReturnSize;
     NTSTATUS Status;
     ULONG DiskNumber;
-    WCHAR Buffer[MAX_PATH];
-    UNICODE_STRING Name;
     HANDLE FileHandle;
+    UNICODE_STRING Name;
+    WCHAR Buffer[MAX_PATH];
 
     List = (PPARTLIST)RtlAllocateHeap(ProcessHeap,
                                       0,
@@ -2768,37 +2815,34 @@ GetNextUnpartitionedEntry(
 BOOLEAN
 CreatePrimaryPartition(
     IN PPARTLIST List,
-    IN PPARTENTRY SelectedEntry,
+    IN OUT PPARTENTRY PartEntry,
     IN ULONGLONG SectorCount,
     IN BOOLEAN AutoCreate)
 {
     ERROR_NUMBER Error;
-    PPARTENTRY PartEntry;
 
     DPRINT1("CreatePrimaryPartition(%I64u)\n", SectorCount);
 
-    if (List == NULL ||
-        SelectedEntry == NULL ||
-        SelectedEntry->DiskEntry == NULL ||
-        SelectedEntry->IsPartitioned)
+    if (List == NULL || PartEntry == NULL ||
+        PartEntry->DiskEntry == NULL || PartEntry->IsPartitioned)
     {
         return FALSE;
     }
 
-    Error = PrimaryPartitionCreationChecks(SelectedEntry);
+    Error = PrimaryPartitionCreationChecks(PartEntry);
     if (Error != NOT_AN_ERROR)
     {
         DPRINT1("PrimaryPartitionCreationChecks() failed with error %lu\n", Error);
         return FALSE;
     }
 
-    /* Convert the current entry, or insert and initialize a new partition entry */
-    PartEntry = InitializePartitionEntry(SelectedEntry->DiskEntry, SelectedEntry, SectorCount, AutoCreate);
-    if (PartEntry == NULL)
+    /* Initialize the partition entry, inserting a new blank region if needed */
+    if (!InitializePartitionEntry(PartEntry, SectorCount, AutoCreate))
         return FALSE;
 
-    UpdateDiskLayout(PartEntry->DiskEntry);
+    ASSERT(PartEntry->LogicalPartition == FALSE);
 
+    UpdateDiskLayout(PartEntry->DiskEntry);
     AssignDriveLetters(List);
 
     return TRUE;
@@ -2830,40 +2874,37 @@ AddLogicalDiskSpace(
         DPRINT1("Failed to create a new empty region for extended partition space!\n");
         return;
     }
-    NewPartEntry->LogicalPartition = TRUE;
 }
 
 BOOLEAN
 CreateExtendedPartition(
     IN PPARTLIST List,
-    IN PPARTENTRY SelectedEntry,
+    IN OUT PPARTENTRY PartEntry,
     IN ULONGLONG SectorCount)
 {
     ERROR_NUMBER Error;
-    PPARTENTRY PartEntry;
 
     DPRINT1("CreateExtendedPartition(%I64u)\n", SectorCount);
 
-    if (List == NULL ||
-        SelectedEntry == NULL ||
-        SelectedEntry->DiskEntry == NULL ||
-        SelectedEntry->IsPartitioned)
+    if (List == NULL || PartEntry == NULL ||
+        PartEntry->DiskEntry == NULL || PartEntry->IsPartitioned)
     {
         return FALSE;
     }
 
-    Error = ExtendedPartitionCreationChecks(SelectedEntry);
+    Error = ExtendedPartitionCreationChecks(PartEntry);
     if (Error != NOT_AN_ERROR)
     {
         DPRINT1("ExtendedPartitionCreationChecks() failed with error %lu\n", Error);
         return FALSE;
     }
 
-    /* Convert the current entry, or insert and initialize a new partition entry */
-    PartEntry = InitializePartitionEntry(SelectedEntry->DiskEntry, SelectedEntry, SectorCount, FALSE);
-    if (PartEntry == NULL)
+    /* Initialize the partition entry, inserting a new blank region if needed */
+    if (!InitializePartitionEntry(PartEntry, SectorCount, FALSE))
         return FALSE;
 
+    ASSERT(PartEntry->LogicalPartition == FALSE);
+
     if (PartEntry->StartSector.QuadPart < 1450560)
     {
         /* Partition starts below the 8.4GB boundary ==> CHS partition */
@@ -2884,7 +2925,6 @@ CreateExtendedPartition(
     AddLogicalDiskSpace(PartEntry->DiskEntry);
 
     UpdateDiskLayout(PartEntry->DiskEntry);
-
     AssignDriveLetters(List);
 
     return TRUE;
@@ -2893,45 +2933,39 @@ CreateExtendedPartition(
 BOOLEAN
 CreateLogicalPartition(
     IN PPARTLIST List,
-    IN PPARTENTRY SelectedEntry,
+    IN OUT PPARTENTRY PartEntry,
     IN ULONGLONG SectorCount,
     IN BOOLEAN AutoCreate)
 {
     ERROR_NUMBER Error;
-    PPARTENTRY PartEntry;
 
     DPRINT1("CreateLogicalPartition(%I64u)\n", SectorCount);
 
-    if (List == NULL ||
-        SelectedEntry == NULL ||
-        SelectedEntry->DiskEntry == NULL ||
-        SelectedEntry->IsPartitioned)
+    if (List == NULL || PartEntry == NULL ||
+        PartEntry->DiskEntry == NULL || PartEntry->IsPartitioned)
     {
         return FALSE;
     }
 
-    Error = LogicalPartitionCreationChecks(SelectedEntry);
+    Error = LogicalPartitionCreationChecks(PartEntry);
     if (Error != NOT_AN_ERROR)
     {
         DPRINT1("LogicalPartitionCreationChecks() failed with error %lu\n", Error);
         return FALSE;
     }
 
-    /* Convert the current entry, or insert and initialize a new partition entry */
-    PartEntry = InitializePartitionEntry(SelectedEntry->DiskEntry, SelectedEntry, SectorCount, AutoCreate);
-    if (PartEntry == NULL)
+    /* Initialize the partition entry, inserting a new blank region if needed */
+    if (!InitializePartitionEntry(PartEntry, SectorCount, AutoCreate))
         return FALSE;
 
-    PartEntry->LogicalPartition = TRUE;
+    ASSERT(PartEntry->LogicalPartition == TRUE);
 
     UpdateDiskLayout(PartEntry->DiskEntry);
-
     AssignDriveLetters(List);
 
     return TRUE;
 }
 
-static
 NTSTATUS
 DismountVolume(
     IN PPARTENTRY PartEntry)
@@ -2948,7 +2982,9 @@ DismountVolume(
     if (!PartEntry->IsPartitioned ||
         IsContainerPartition(PartEntry->PartitionType)   ||
         !IsRecognizedPartition(PartEntry->PartitionType) ||
-        PartEntry->FormatState == Unformatted /* || PartEntry->FormatState == UnknownFormat */ ||
+        PartEntry->FormatState == UnknownFormat ||
+        // NOTE: If FormatState == Unformatted but *FileSystem != 0 this means
+        // it has been usually mounted with RawFS and thus needs to be dismounted.
         !*PartEntry->FileSystem ||
         PartEntry->PartitionNumber == 0)
     {
@@ -3049,10 +3085,8 @@ DeletePartition(
     PPARTENTRY LogicalPartEntry;
     PLIST_ENTRY Entry;
 
-    if (List == NULL ||
-        PartEntry == NULL ||
-        PartEntry->DiskEntry == NULL ||
-        PartEntry->IsPartitioned == FALSE)
+    if (List == NULL || PartEntry == NULL ||
+        PartEntry->DiskEntry == NULL || PartEntry->IsPartitioned == FALSE)
     {
         return FALSE;
     }
@@ -3154,13 +3188,15 @@ DeletePartition(
     {
         /* Nothing to merge but change the current entry */
         PartEntry->IsPartitioned = FALSE;
+        PartEntry->OnDiskPartitionNumber = 0;
+        PartEntry->PartitionNumber = 0;
+        // PartEntry->PartitionIndex = 0;
+        PartEntry->BootIndicator = FALSE;
         PartEntry->PartitionType = PARTITION_ENTRY_UNUSED;
         PartEntry->FormatState = Unformatted;
         PartEntry->FileSystem[0] = L'\0';
         PartEntry->DriveLetter = 0;
-        PartEntry->OnDiskPartitionNumber = 0;
-        PartEntry->PartitionNumber = 0;
-        // PartEntry->PartitionIndex = 0;
+        RtlZeroMemory(PartEntry->VolumeLabel, sizeof(PartEntry->VolumeLabel));
 
         /* Optionally return the freed region */
         if (FreeRegion)
@@ -3168,7 +3204,6 @@ DeletePartition(
     }
 
     UpdateDiskLayout(DiskEntry);
-
     AssignDriveLetters(List);
 
     return TRUE;
@@ -3179,6 +3214,28 @@ DeletePartition(
  * On MBR disks, partition with the Active/Boot flag set;
  * on GPT disks, partition with the correct GUID.
  */
+BOOLEAN
+IsPartitionActive(
+    IN PPARTENTRY PartEntry)
+{
+    // TODO: Support for GPT disks!
+
+    if (IsContainerPartition(PartEntry->PartitionType))
+        return FALSE;
+
+    /* Check if the partition is partitioned, used and active */
+    if (PartEntry->IsPartitioned &&
+        // !IsContainerPartition(PartEntry->PartitionType) &&
+        PartEntry->BootIndicator)
+    {
+        /* Yes it is */
+        ASSERT(PartEntry->PartitionType != PARTITION_ENTRY_UNUSED);
+        return TRUE;
+    }
+
+    return FALSE;
+}
+
 static
 PPARTENTRY
 GetActiveDiskPartition(
@@ -3210,17 +3267,11 @@ GetActiveDiskPartition(
     {
         /* Retrieve the partition */
         PartEntry = CONTAINING_RECORD(ListEntry, PARTENTRY, ListEntry);
-
-        // TODO: Support for GPT disks!
-
-        /* Check if the partition is partitioned, used and active */
-        if (PartEntry->IsPartitioned &&
-            // !IsContainerPartition(PartEntry->PartitionType) &&
-            PartEntry->BootIndicator)
+        if (IsPartitionActive(PartEntry))
         {
-            /* Yes, we found it */
+            /* Yes, we've found it */
             ASSERT(DiskEntry == PartEntry->DiskEntry);
-            ASSERT(PartEntry->PartitionType != PARTITION_ENTRY_UNUSED);
+            ASSERT(PartEntry->IsPartitioned);
 
             ActivePartition = PartEntry;
 
@@ -3247,7 +3298,7 @@ BOOLEAN
 IsSupportedActivePartition(
     IN PPARTENTRY PartEntry)
 {
-    /* Check the type and the filesystem of this partition */
+    /* Check the type and the file system of this partition */
 
     /*
      * We do not support extended partition containers (on MBR disks) marked
@@ -3276,9 +3327,13 @@ IsSupportedActivePartition(
      * NOTE also that for those architectures looking for a
      * partition boot indicator is insufficient.
      */
-    if ((PartEntry->FormatState == Unformatted ) ||
-        (PartEntry->FormatState == Preformatted) ||
-        (PartEntry->FormatState == Formatted   ))
+    if (PartEntry->FormatState == Unformatted)
+    {
+        /* If this partition is mounted, it would use RawFS ("RAW") */
+        return TRUE;
+    }
+    else if ((PartEntry->FormatState == Preformatted) ||
+             (PartEntry->FormatState == Formatted))
     {
         ASSERT(*PartEntry->FileSystem);
 
@@ -3286,8 +3341,7 @@ IsSupportedActivePartition(
         if (wcsicmp(PartEntry->FileSystem, L"FAT")   == 0 ||
             wcsicmp(PartEntry->FileSystem, L"FAT32") == 0 ||
          // wcsicmp(PartEntry->FileSystem, L"NTFS")  == 0 ||
-            wcsicmp(PartEntry->FileSystem, L"BTRFS") == 0 ||
-            wcsicmp(PartEntry->FileSystem, L"RAW")   == 0)
+            wcsicmp(PartEntry->FileSystem, L"BTRFS") == 0)
         {
             return TRUE;
         }
diff --git a/base/setup/lib/utils/partlist.h b/base/setup/lib/utils/partlist.h
index fc31cc13331..19c24e1224e 100644
--- a/base/setup/lib/utils/partlist.h
+++ b/base/setup/lib/utils/partlist.h
@@ -44,7 +44,6 @@ typedef struct _PARTENTRY
 
     BOOLEAN BootIndicator;
     UCHAR PartitionType;
-    ULONG HiddenSectors;
     ULONG OnDiskPartitionNumber; /* Enumerated partition number (primary partitions first, excluding the extended partition container, then the logical partitions) */
     ULONG PartitionNumber;       /* Current partition number, only valid for the currently running NTOS instance */
     ULONG PartitionIndex;        /* Index in the LayoutBuffer->PartitionEntry[] cached array of the corresponding DiskEntry */
@@ -231,6 +230,9 @@ BOOLEAN
 IsSuperFloppy(
     IN PDISKENTRY DiskEntry);
 
+BOOLEAN
+IsPartitionActive(
+    IN PPARTENTRY PartEntry);
 
 PPARTLIST
 CreatePartitionList(VOID);
@@ -294,23 +296,27 @@ GetPrevPartition(
 BOOLEAN
 CreatePrimaryPartition(
     IN PPARTLIST List,
-    IN PPARTENTRY SelectedEntry,
+    IN OUT PPARTENTRY PartEntry,
     IN ULONGLONG SectorCount,
     IN BOOLEAN AutoCreate);
 
 BOOLEAN
 CreateExtendedPartition(
     IN PPARTLIST List,
-    IN PPARTENTRY SelectedEntry,
+    IN OUT PPARTENTRY PartEntry,
     IN ULONGLONG SectorCount);
 
 BOOLEAN
 CreateLogicalPartition(
     IN PPARTLIST List,
-    IN PPARTENTRY SelectedEntry,
+    IN OUT PPARTENTRY PartEntry,
     IN ULONGLONG SectorCount,
     IN BOOLEAN AutoCreate);
 
+NTSTATUS
+DismountVolume(
+    IN PPARTENTRY PartEntry);
+
 BOOLEAN
 DeletePartition(
     IN PPARTLIST List,
diff --git a/base/setup/usetup/usetup.c b/base/setup/usetup/usetup.c
index 8aaf3cc5831..daf786df87d 100644
--- a/base/setup/usetup/usetup.c
+++ b/base/setup/usetup/usetup.c
@@ -46,12 +46,19 @@ BOOLEAN IsUnattendedSetup = FALSE;
 
 static USETUP_DATA USetupData;
 
-/* Partition where to perform the installation */
+/* The partition where to perform the installation */
 static PPARTENTRY InstallPartition = NULL;
-// static PPARTENTRY SystemPartition = NULL;    // The system partition we will actually use (can be different from PartitionList->SystemPartition in case we install on removable disk)
-
-// FIXME: Is it really useful?? Just used for SetDefaultPagefile...
-static WCHAR DestinationDriveLetter;
+/*
+ * The system partition we will actually use. It can be different from
+ * PartitionList->SystemPartition in case we don't support it, or we install
+ * on a removable disk.
+ * We may indeed not support the original system partition in case we do not
+ * have write support on it. Please note that this situation is partly a HACK
+ * and MUST NEVER happen on architectures where real system partitions are
+ * mandatory (because then they are formatted in FAT FS and we support write
+ * operation on them).
+ */
+static PPARTENTRY SystemPartition = NULL;
 
 
 /* OTHER Stuff *****/
@@ -1465,7 +1472,6 @@ SelectPartitionPage(PINPUT_RECORD Ir)
         PartitionList = CreatePartitionList();
         if (PartitionList == NULL)
         {
-            /* FIXME: show an error dialog */
             MUIDisplayError(ERROR_DRIVE_INFORMATION, Ir, POPUP_WAIT_ENTER);
             return QUIT_PAGE;
         }
@@ -1784,7 +1790,7 @@ SelectPartitionPage(PINPUT_RECORD Ir)
 
 // FIXME TODO: PartitionList->SystemPartition is not yet initialized!!!!
             if (CurrentPartition == PartitionList->SystemPartition ||
-                CurrentPartition->BootIndicator)
+                IsPartitionActive(CurrentPartition))
             {
                 return CONFIRM_DELETE_SYSTEM_PARTITION_PAGE;
             }
@@ -1879,7 +1885,7 @@ ShowPartitionSizeInputBox(SHORT Left,
             CONSOLE_SetCursorType(TRUE, FALSE);
             break;
         }
-        else if (Ir.Event.KeyEvent.wVirtualKeyCode == VK_ESCAPE)    /* ESCAPE */
+        else if (Ir.Event.KeyEvent.wVirtualKeyCode == VK_ESCAPE)    /* ESC */
         {
             if (Cancel != NULL)
                 *Cancel = TRUE;
@@ -2733,20 +2739,21 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
             //
             return QUIT_PAGE;
         }
+        SystemPartition = PartitionList->SystemPartition;
 
         /*
          * If the system partition can be created in some
          * non-partitioned space, create it now.
          */
-        if (!PartitionList->SystemPartition->IsPartitioned)
+        if (!SystemPartition->IsPartitioned)
         {
             // if (IsUnattendedSetup)
             {
                 CreatePrimaryPartition(PartitionList,
-                                       PartitionList->SystemPartition,
-                                       0LL, // PartitionList->SystemPartition->SectorCount.QuadPart,
+                                       SystemPartition,
+                                       0LL, // SystemPartition->SectorCount.QuadPart,
                                        TRUE);
-                ASSERT(PartitionList->SystemPartition->IsPartitioned);
+                ASSERT(SystemPartition->IsPartitioned);
             }
             // else
             {
@@ -2767,8 +2774,8 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
          * installation partitions.
          */
         InstallPartition->NeedsCheck = TRUE;
-        if (PartitionList->SystemPartition != InstallPartition)
-            PartitionList->SystemPartition->NeedsCheck = TRUE;
+        if (SystemPartition != InstallPartition)
+            SystemPartition->NeedsCheck = TRUE;
 
         /*
          * In case we just repair an existing installation, or make
@@ -2782,7 +2789,7 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
             return CHECK_FILE_SYSTEM_PAGE;
     }
 
-    // ASSERT(PartitionList->SystemPartition->IsPartitioned);
+    // ASSERT(SystemPartition->IsPartitioned);
 
     /* Reset the filesystem list for each partition that is to be formatted */
     ResetFileSystemList();
@@ -2799,12 +2806,12 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
              * and start by formatting the installation partition instead.
              */
 
-            ASSERT(PartitionList->SystemPartition->IsPartitioned);
+            ASSERT(SystemPartition->IsPartitioned);
 
-            if ((PartitionList->SystemPartition != InstallPartition) &&
-                (PartitionList->SystemPartition->FormatState == Unformatted))
+            if ((SystemPartition != InstallPartition) &&
+                (SystemPartition->FormatState == Unformatted))
             {
-                TempPartition = PartitionList->SystemPartition;
+                TempPartition = SystemPartition;
                 TempPartition->NeedsCheck = TRUE;
 
                 // TODO: Should we let the user using a custom file-system,
@@ -2819,14 +2826,14 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
                 TempPartition = InstallPartition;
                 TempPartition->NeedsCheck = TRUE;
 
-                if (PartitionList->SystemPartition != InstallPartition)
+                if (SystemPartition != InstallPartition)
                 {
                     /* The system partition is separate, so it had better be formatted! */
-                    ASSERT((PartitionList->SystemPartition->FormatState == Preformatted) ||
-                           (PartitionList->SystemPartition->FormatState == Formatted));
+                    ASSERT((SystemPartition->FormatState == Preformatted) ||
+                           (SystemPartition->FormatState == Formatted));
 
                     /* Require a filesystem check on the system partition too */
-                    PartitionList->SystemPartition->NeedsCheck = TRUE;
+                    SystemPartition->NeedsCheck = TRUE;
                 }
 
                 FormatState = FormatInstallPartition;
@@ -2883,7 +2890,7 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
         default:
         {
             DPRINT1("FormatState: Invalid value %ld\n", FormatState);
-            /* FIXME: show an error dialog */
+            ASSERT(FALSE);
             return QUIT_PAGE;
         }
     }
@@ -2971,10 +2978,23 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
                 break;
 
             default:
+                ASSERT(FALSE);
                 break;
         }
 
-        CONSOLE_SetTextXY(6, 10, MUIGetString(STRING_PARTFORMAT));
+        CONSOLE_PrintTextXY(8, 10, MUIGetString(STRING_HDINFOPARTZEROED_1),
+                            DiskEntry->DiskNumber,
+                            DiskSize,
+                            DiskUnit,
+                            DiskEntry->Port,
+                            DiskEntry->Bus,
+                            DiskEntry->Id,
+                            &DiskEntry->DriverName,
+                            DiskEntry->DiskStyle == PARTITION_STYLE_MBR ? "MBR" :
+                            DiskEntry->DiskStyle == PARTITION_STYLE_GPT ? "GPT" :
+                                                                          "RAW");
+
+        CONSOLE_SetTextXY(6, 12, MUIGetString(STRING_PARTFORMAT));
     }
     else
     {
@@ -3108,7 +3128,7 @@ SelectFileSystemPage(PINPUT_RECORD Ir)
                  * filesystem checks on it, unless it is either the system
                  * or the installation partition.
                  */
-                if (TempPartition != PartitionList->SystemPartition &&
+                if (TempPartition != SystemPartition &&
                     TempPartition != InstallPartition)
                 {
                     PartEntry->NeedsCheck = FALSE;
@@ -3435,15 +3455,10 @@ CheckFileSystemPage(PINPUT_RECORD Ir)
     else if (!NT_SUCCESS(Status))
     {
         DPRINT("ChkdskPartition() failed with status 0x%08lx\n", Status);
-        // sprintf(Buffer, "Setup failed to verify the selected partition.\n"
-        sprintf(Buffer, "ChkDsk detected some disk errors.\n"
-                "(Status 0x%08lx).\n", Status);
+        sprintf(Buffer, "ChkDsk detected some disk errors.\n(Status 0x%08lx).\n", Status);
         PopupError(Buffer,
-                   // MUIGetString(STRING_REBOOTCOMPUTER),
                    MUIGetString(STRING_CONTINUE),
                    Ir, POPUP_WAIT_ENTER);
-
-        // return QUIT_PAGE;
     }
 
     PartEntry->NeedsCheck = FALSE;
@@ -3451,28 +3466,6 @@ CheckFileSystemPage(PINPUT_RECORD Ir)
 }
 
 
-static NTSTATUS
-BuildInstallPaths(
-    IN PCWSTR InstallDir,
-    IN PPARTENTRY PartEntry)
-{
-    NTSTATUS Status;
-
-    Status = InitDestinationPaths(&USetupData, InstallDir, PartEntry);
-
-    if (!NT_SUCCESS(Status))
-    {
-        DPRINT1("InitDestinationPaths() failed with status 0x%08lx\n", Status);
-        return Status;
-    }
-
-    /* Initialize DestinationDriveLetter */
-    DestinationDriveLetter = PartEntry->DriveLetter;
-
-    return STATUS_SUCCESS;
-}
-
-
 static BOOLEAN
 IsValidPath(
     IN PCWSTR InstallDir)
@@ -3563,10 +3556,10 @@ InstallDirectoryPage(PINPUT_RECORD Ir)
      */
     if ((RepairUpdateFlag || IsUnattendedSetup) && IsValidPath(InstallDir))
     {
-        Status = BuildInstallPaths(InstallDir, InstallPartition);
+        Status = InitDestinationPaths(&USetupData, InstallDir, InstallPartition);
         if (!NT_SUCCESS(Status))
         {
-            DPRINT1("BuildInstallPaths() failed. Status code: 0x%lx", Status);
+            DPRINT1("InitDestinationPaths() failed. Status code: 0x%lx", Status);
             MUIDisplayError(ERROR_NO_BUILD_PATH, Ir, POPUP_WAIT_ENTER);
             return QUIT_PAGE;
         }
@@ -3667,10 +3660,10 @@ InstallDirectoryPage(PINPUT_RECORD Ir)
                 return INSTALL_DIRECTORY_PAGE;
             }
 
-            Status = BuildInstallPaths(InstallDir, InstallPartition);
+            Status = InitDestinationPaths(&USetupData, InstallDir, InstallPartition);
             if (!NT_SUCCESS(Status))
             {
-                DPRINT1("BuildInstallPaths() failed. Status code: 0x%lx", Status);
+                DPRINT1("InitDestinationPaths() failed. Status code: 0x%lx", Status);
                 MUIDisplayError(ERROR_NO_BUILD_PATH, Ir, POPUP_WAIT_ENTER);
                 return QUIT_PAGE;
             }
@@ -4068,7 +4061,7 @@ RegistryPage(PINPUT_RECORD Ir)
     Error = UpdateRegistry(&USetupData,
                            RepairUpdateFlag,
                            PartitionList,
-                           DestinationDriveLetter,
+                           InstallPartition->DriveLetter,
                            SelectedLanguageId,
                            RegistryStatus);
     if (Error != ERROR_SUCCESS)
@@ -4114,17 +4107,17 @@ BootLoaderPage(PINPUT_RECORD Ir)
 
     CONSOLE_SetStatusText(MUIGetString(STRING_PLEASEWAIT));
 
-    ASSERT(PartitionList->SystemPartition->IsPartitioned && PartitionList->SystemPartition->PartitionNumber != 0);
+    ASSERT(SystemPartition->IsPartitioned && SystemPartition->PartitionNumber != 0);
 
     RtlFreeUnicodeString(&USetupData.SystemRootPath);
     RtlStringCchPrintfW(PathBuffer, ARRAYSIZE(PathBuffer),
             L"\\Device\\Harddisk%lu\\Partition%lu\\",
-            PartitionList->SystemPartition->DiskEntry->DiskNumber,
-            PartitionList->SystemPartition->PartitionNumber);
+            SystemPartition->DiskEntry->DiskNumber,
+            SystemPartition->PartitionNumber);
     RtlCreateUnicodeString(&USetupData.SystemRootPath, PathBuffer);
     DPRINT1("SystemRootPath: %wZ\n", &USetupData.SystemRootPath);
 
-    PartitionType = PartitionList->SystemPartition->PartitionType;
+    PartitionType = SystemPartition->PartitionType;
 
     /* For unattended setup, skip MBR installation or install on floppy if needed */
     if (IsUnattendedSetup)
@@ -4392,11 +4385,11 @@ BootLoaderHarddiskVbrPage(PINPUT_RECORD Ir)
     Status = InstallVBRToPartition(&USetupData.SystemRootPath,
                                    &USetupData.SourceRootPath,
                                    &USetupData.DestinationArcPath,
-                                   PartitionList->SystemPartition->PartitionType);
+                                   SystemPartition->PartitionType);
     if (!NT_SUCCESS(Status))
     {
         MUIDisplayError(ERROR_WRITE_BOOT, Ir, POPUP_WAIT_ENTER,
-                        PartitionList->SystemPartition->FileSystem);
+                        SystemPartition->FileSystem);
         return QUIT_PAGE;
     }
 
@@ -4429,20 +4422,20 @@ BootLoaderHarddiskMbrPage(PINPUT_RECORD Ir)
     Status = InstallVBRToPartition(&USetupData.SystemRootPath,
                                    &USetupData.SourceRootPath,
                                    &USetupData.DestinationArcPath,
-                                   PartitionList->SystemPartition->PartitionType);
+                                   SystemPartition->PartitionType);
     if (!NT_SUCCESS(Status))
     {
         MUIDisplayError(ERROR_WRITE_BOOT, Ir, POPUP_WAIT_ENTER,
-                        PartitionList->SystemPartition->FileSystem);
+                        SystemPartition->FileSystem);
         return QUIT_PAGE;
     }
 
     /* Step 2: Write the MBR if the disk containing the system partition is not a super-floppy */
-    if (!IsSuperFloppy(PartitionList->SystemPartition->DiskEntry))
+    if (!IsSuperFloppy(SystemPartition->DiskEntry))
     {
         RtlStringCchPrintfW(DestinationDevicePathBuffer, ARRAYSIZE(DestinationDevicePathBuffer),
                 L"\\Device\\Harddisk%d\\Partition0",
-                PartitionList->SystemPartition->DiskEntry->DiskNumber);
+                SystemPartition->DiskEntry->DiskNumber);
         Status = InstallMbrBootCodeToDisk(&USetupData.SystemRootPath,
                                           &USetupData.SourceRootPath,
                                           DestinationDevicePathBuffer);