diff --git a/cmd/runhcs/create-scratch.go b/cmd/runhcs/create-scratch.go
index 78bb614171..2572186856 100644
--- a/cmd/runhcs/create-scratch.go
+++ b/cmd/runhcs/create-scratch.go
@@ -52,6 +52,9 @@ var createScratchCommand = cli.Command{
 		// 256MB with boot from vhd supported.
 		opts.MemorySizeInMB = 256
 		opts.VPMemDeviceCount = 1
+		// Default SCSI controller count is 4, we don't need that for this UVM,
+		// bring it back to 1 to avoid any confusion with SCSI controller numbers.
+		opts.SCSIControllerCount = 1
 
 		sizeGB := uint32(context.Uint("sizeGB"))
 		if sizeGB == 0 {
diff --git a/cmd/runhcs/prepare-disk.go b/cmd/runhcs/prepare-disk.go
index 6349e02911..6d0a437af6 100644
--- a/cmd/runhcs/prepare-disk.go
+++ b/cmd/runhcs/prepare-disk.go
@@ -44,6 +44,9 @@ var prepareDiskCommand = cli.Command{
 		}
 
 		opts := uvm.NewDefaultOptionsLCOW("preparedisk-uvm", context.GlobalString("owner"))
+		// Default SCSI controller count is 4, we don't need that for this UVM,
+		// bring it back to 1 to avoid any confusion with SCSI controller numbers.
+		opts.SCSIControllerCount = 1
 
 		preparediskUVM, err := uvm.CreateLCOW(ctx, opts)
 		if err != nil {
diff --git a/internal/guest/storage/scsi/scsi.go b/internal/guest/storage/scsi/scsi.go
index f5231dfb9d..7af2db325d 100644
--- a/internal/guest/storage/scsi/scsi.go
+++ b/internal/guest/storage/scsi/scsi.go
@@ -8,7 +8,10 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"path"
 	"path/filepath"
+	"strconv"
+	"strings"
 	"time"
 
 	"github.com/pkg/errors"
@@ -20,6 +23,7 @@ import (
 	dm "github.com/Microsoft/hcsshim/internal/guest/storage/devicemapper"
 	"github.com/Microsoft/hcsshim/internal/log"
 	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
 	"github.com/Microsoft/hcsshim/internal/protocol/guestresource"
 	"github.com/Microsoft/hcsshim/pkg/securitypolicy"
 )
@@ -39,11 +43,45 @@ var (
 )
 
 const (
-	scsiDevicesPath = "/sys/bus/scsi/devices"
-	verityDeviceFmt = "verity-scsi-contr%d-lun%d-%s"
+	scsiDevicesPath  = "/sys/bus/scsi/devices"
+	vmbusDevicesPath = "/sys/bus/vmbus/devices"
+	verityDeviceFmt  = "verity-scsi-contr%d-lun%d-%s"
 )
 
-// Mount creates a mount from the SCSI device on `controller` index `lun` to
+// fetchActualControllerNumber retrieves the actual controller number assigned to a SCSI controller
+// with number `passedController`.
+// When HCS creates the UVM it adds 4 SCSI controllers to the UVM but the 1st SCSI
+// controller according to HCS can actually show up as 2nd, 3rd or 4th controller inside
+// the UVM. So the i'th controller from HCS' perspective could actually be j'th controller
+// inside the UVM. However, we can refer to the SCSI controllers with their GUIDs (that
+// are hardcoded) and then using that GUID find out the SCSI controller number inside the
+// guest. This function does exactly that.
+func fetchActualControllerNumber(ctx context.Context, passedController uint8) (uint8, error) {
+	// find the controller number by looking for a file named host<N> (e.g host1, host3 etc.)
+	// `N` is the controller number.
+	// Full file path would be /sys/bus/vmbus/devices/<controller-guid>/host<N>.
+	controllerDirPath := path.Join(vmbusDevicesPath, guestrequest.ScsiControllerGuids[passedController])
+	entries, err := ioutil.ReadDir(controllerDirPath)
+	if err != nil {
+		return 0, err
+	}
+
+	for _, entry := range entries {
+		baseName := path.Base(entry.Name())
+		if !strings.HasPrefix(baseName, "host") {
+			continue
+		}
+		controllerStr := baseName[len("host"):]
+		controllerNum, err := strconv.ParseUint(controllerStr, 10, 8)
+		if err != nil {
+			return 0, fmt.Errorf("failed to parse controller number from %s: %w", baseName, err)
+		}
+		return uint8(controllerNum), nil
+	}
+	return 0, fmt.Errorf("host<N> directory not found inside %s", controllerDirPath)
+}
+
+// mount creates a mount from the SCSI device on `controller` index `lun` to
 // `target`
 //
 // `target` will be created. On mount failure the created `target` will be
@@ -51,7 +89,7 @@ const (
 //
 // If `encrypted` is set to true, the SCSI device will be encrypted using
 // dm-crypt.
-func Mount(
+func mount(
 	ctx context.Context,
 	controller,
 	lun uint8,
@@ -159,10 +197,30 @@ func Mount(
 	return nil
 }
 
-// Unmount unmounts a SCSI device mounted at `target`.
+// Mount is just a wrapper over actual mount call. This wrapper finds out the controller
+// number from the controller GUID string and calls mount.
+func Mount(
+	ctx context.Context,
+	controller,
+	lun uint8,
+	target string,
+	readonly bool,
+	encrypted bool,
+	options []string,
+	verityInfo *guestresource.DeviceVerityInfo,
+	securityPolicy securitypolicy.SecurityPolicyEnforcer,
+) (err error) {
+	cNum, err := fetchActualControllerNumber(ctx, controller)
+	if err != nil {
+		return err
+	}
+	return mount(ctx, cNum, lun, target, readonly, encrypted, options, verityInfo, securityPolicy)
+}
+
+// unmount unmounts a SCSI device mounted at `target`.
 //
 // If `encrypted` is true, it removes all its associated dm-crypto state.
-func Unmount(
+func unmount(
 	ctx context.Context,
 	controller,
 	lun uint8,
@@ -206,6 +264,24 @@ func Unmount(
 	return nil
 }
 
+// Unmount is just a wrapper over actual unmount call. This wrapper finds out the controller
+// number from the controller GUID string and calls mount.
+func Unmount(
+	ctx context.Context,
+	controller,
+	lun uint8,
+	target string,
+	encrypted bool,
+	verityInfo *guestresource.DeviceVerityInfo,
+	securityPolicy securitypolicy.SecurityPolicyEnforcer,
+) (err error) {
+	cNum, err := fetchActualControllerNumber(ctx, controller)
+	if err != nil {
+		return err
+	}
+	return unmount(ctx, cNum, lun, target, encrypted, verityInfo, securityPolicy)
+}
+
 // ControllerLunToName finds the `/dev/sd*` path to the SCSI device on
 // `controller` index `lun`.
 func ControllerLunToName(ctx context.Context, controller, lun uint8) (_ string, err error) {
@@ -217,8 +293,7 @@ func ControllerLunToName(ctx context.Context, controller, lun uint8) (_ string,
 		trace.Int64Attribute("controller", int64(controller)),
 		trace.Int64Attribute("lun", int64(lun)))
 
-	scsiID := fmt.Sprintf("0:0:%d:%d", controller, lun)
-
+	scsiID := fmt.Sprintf("%d:0:0:%d", controller, lun)
 	// Devices matching the given SCSI code should each have a subdirectory
 	// under /sys/bus/scsi/devices/<scsiID>/block.
 	blockPath := filepath.Join(scsiDevicesPath, scsiID, "block")
@@ -249,11 +324,11 @@ func ControllerLunToName(ctx context.Context, controller, lun uint8) (_ string,
 	return devicePath, nil
 }
 
-// UnplugDevice finds the SCSI device on `controller` index `lun` and issues a
+// unplugDevice finds the SCSI device on `controller` index `lun` and issues a
 // guest initiated unplug.
 //
 // If the device is not attached returns no error.
-func UnplugDevice(ctx context.Context, controller, lun uint8) (err error) {
+func unplugDevice(ctx context.Context, controller, lun uint8) (err error) {
 	_, span := trace.StartSpan(ctx, "scsi::UnplugDevice")
 	defer span.End()
 	defer func() { oc.SetSpanStatus(span, err) }()
@@ -262,7 +337,7 @@ func UnplugDevice(ctx context.Context, controller, lun uint8) (err error) {
 		trace.Int64Attribute("controller", int64(controller)),
 		trace.Int64Attribute("lun", int64(lun)))
 
-	scsiID := fmt.Sprintf("0:0:%d:%d", controller, lun)
+	scsiID := fmt.Sprintf("%d:0:0:%d", controller, lun)
 	f, err := os.OpenFile(filepath.Join(scsiDevicesPath, scsiID, "delete"), os.O_WRONLY, 0644)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -277,3 +352,13 @@ func UnplugDevice(ctx context.Context, controller, lun uint8) (err error) {
 	}
 	return nil
 }
+
+// UnplugDevice is just a wrapper over actual unplugDevice call. This wrapper finds out the controller
+// number from the controller GUID string and calls unplugDevice.
+func UnplugDevice(ctx context.Context, controller, lun uint8) (err error) {
+	cNum, err := fetchActualControllerNumber(ctx, controller)
+	if err != nil {
+		return err
+	}
+	return unplugDevice(ctx, cNum, lun)
+}
diff --git a/internal/guest/storage/scsi/scsi_test.go b/internal/guest/storage/scsi/scsi_test.go
index 4ac33ebcb4..c4cb2f55ae 100644
--- a/internal/guest/storage/scsi/scsi_test.go
+++ b/internal/guest/storage/scsi/scsi_test.go
@@ -37,7 +37,7 @@ func Test_Mount_Mkdir_Fails_Error(t *testing.T) {
 		return "", nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -74,7 +74,7 @@ func Test_Mount_Mkdir_ExpectedPath(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -111,7 +111,7 @@ func Test_Mount_Mkdir_ExpectedPerm(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -148,7 +148,7 @@ func Test_Mount_ControllerLunToName_Valid_Controller(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		expectedController,
 		0,
@@ -185,7 +185,7 @@ func Test_Mount_ControllerLunToName_Valid_Lun(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		expectedLun,
@@ -225,7 +225,7 @@ func Test_Mount_Calls_RemoveAll_OnMountFailure(t *testing.T) {
 		return expectedErr
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -263,7 +263,7 @@ func Test_Mount_Valid_Source(t *testing.T) {
 		}
 		return nil
 	}
-	err := Mount(context.Background(), 0, 0, "/fake/path", false, false, nil, nil, openDoorSecurityPolicyEnforcer())
+	err := mount(context.Background(), 0, 0, "/fake/path", false, false, nil, nil, openDoorSecurityPolicyEnforcer())
 	if err != nil {
 		t.Fatalf("expected nil err, got: %v", err)
 	}
@@ -290,7 +290,7 @@ func Test_Mount_Valid_Target(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -326,7 +326,7 @@ func Test_Mount_Valid_FSType(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -362,7 +362,7 @@ func Test_Mount_Valid_Flags(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -398,7 +398,7 @@ func Test_Mount_Readonly_Valid_Flags(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -433,7 +433,7 @@ func Test_Mount_Valid_Data(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -469,7 +469,7 @@ func Test_Mount_Readonly_Valid_Data(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -506,7 +506,7 @@ func Test_Read_Only_Security_Policy_Enforcement_Mount_Calls(t *testing.T) {
 	}
 
 	enforcer := mountMonitoringSecurityPolicyEnforcer()
-	err := Mount(context.Background(), 0, 0, target, true, false, nil, nil, enforcer)
+	err := mount(context.Background(), 0, 0, target, true, false, nil, nil, enforcer)
 	if err != nil {
 		t.Fatalf("expected nil err, got: %v", err)
 	}
@@ -549,7 +549,7 @@ func Test_Read_Write_Security_Policy_Enforcement_Mount_Calls(t *testing.T) {
 	}
 
 	enforcer := mountMonitoringSecurityPolicyEnforcer()
-	err := Mount(context.Background(), 0, 0, target, false, false, nil, nil, enforcer)
+	err := mount(context.Background(), 0, 0, target, false, false, nil, nil, enforcer)
 	if err != nil {
 		t.Fatalf("expected nil err, got: %v", err)
 	}
@@ -592,12 +592,12 @@ func Test_Security_Policy_Enforcement_Unmount_Calls(t *testing.T) {
 	}
 
 	enforcer := mountMonitoringSecurityPolicyEnforcer()
-	err := Mount(context.Background(), 0, 0, target, true, false, nil, nil, enforcer)
+	err := mount(context.Background(), 0, 0, target, true, false, nil, nil, enforcer)
 	if err != nil {
 		t.Fatalf("expected nil err, got: %v", err)
 	}
 
-	err = Unmount(context.Background(), 0, 0, target, false, nil, enforcer)
+	err = unmount(context.Background(), 0, 0, target, false, nil, enforcer)
 	if err != nil {
 		t.Fatalf("expected nil err, got: %v", err)
 	}
@@ -668,7 +668,7 @@ func Test_CreateVerityTarget_And_Mount_Called_With_Correct_Parameters(t *testing
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
@@ -717,7 +717,7 @@ func Test_osMkdirAllFails_And_RemoveDevice_Called(t *testing.T) {
 		return nil
 	}
 
-	if err := Mount(
+	if err := mount(
 		context.Background(),
 		0,
 		0,
diff --git a/internal/protocol/guestrequest/types.go b/internal/protocol/guestrequest/types.go
index 5c3d7111d4..d8d0c20b10 100644
--- a/internal/protocol/guestrequest/types.go
+++ b/internal/protocol/guestrequest/types.go
@@ -41,3 +41,16 @@ type RS4NetworkModifyRequest struct {
 	RequestType       RequestType `json:"RequestType,omitempty"`
 	Settings          interface{} `json:"Settings,omitempty"`
 }
+
+var (
+	// V5 GUIDs for SCSI controllers
+	// These GUIDs are created with namespace GUID "d422512d-2bf2-4752-809d-7b82b5fcb1b4"
+	// and index as names. For example, first GUID is created like this:
+	// guid.NewV5("d422512d-2bf2-4752-809d-7b82b5fcb1b4", []byte("0"))
+	ScsiControllerGuids = []string{
+		"df6d0690-79e5-55b6-a5ec-c1e2f77f580a",
+		"0110f83b-de10-5172-a266-78bca56bf50a",
+		"b5d2d8d4-3a75-51bf-945b-3444dc6b8579",
+		"305891a9-b251-5dfe-91a2-c25d9212275b",
+	}
+)
diff --git a/internal/protocol/guestrequest/types_test.go b/internal/protocol/guestrequest/types_test.go
new file mode 100644
index 0000000000..52b5807c48
--- /dev/null
+++ b/internal/protocol/guestrequest/types_test.go
@@ -0,0 +1,15 @@
+package guestrequest
+
+import (
+	"github.com/Microsoft/go-winio/pkg/guid"
+	"testing"
+)
+
+func TestGuidValidity(t *testing.T) {
+	for _, g := range ScsiControllerGuids {
+		_, err := guid.FromString(g)
+		if err != nil {
+			t.Fatalf("GUID parsing failed: %s", err)
+		}
+	}
+}
diff --git a/internal/uvm/constants.go b/internal/uvm/constants.go
index 842a8a5e8c..9be9fc4043 100644
--- a/internal/uvm/constants.go
+++ b/internal/uvm/constants.go
@@ -2,6 +2,8 @@ package uvm
 
 import (
 	"errors"
+
+	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
 )
 
 const (
@@ -34,4 +36,7 @@ const (
 var (
 	errNotSupported = errors.New("not supported")
 	errBadUVMOpts   = errors.New("UVM options incorrect")
+
+	// Maximum number of SCSI controllers allowed
+	MaxSCSIControllers = uint32(len(guestrequest.ScsiControllerGuids))
 )
diff --git a/internal/uvm/create.go b/internal/uvm/create.go
index a3d9fcd4e6..1a08bae535 100644
--- a/internal/uvm/create.go
+++ b/internal/uvm/create.go
@@ -94,6 +94,9 @@ type Options struct {
 
 	// NoWritableFileShares disables adding any writable vSMB and Plan9 shares to the UVM
 	NoWritableFileShares bool
+
+	// The number of SCSI controllers. Defaults to 1 for WCOW and 4 for LCOW
+	SCSIControllerCount uint32
 }
 
 // compares the create opts used during template creation with the create opts
@@ -131,8 +134,8 @@ func verifyOptions(ctx context.Context, options interface{}) error {
 		if opts.EnableDeferredCommit && !opts.AllowOvercommit {
 			return errors.New("EnableDeferredCommit is not supported on physically backed VMs")
 		}
-		if opts.SCSIControllerCount > 1 {
-			return errors.New("SCSI controller count must be 0 or 1") // Future extension here for up to 4
+		if opts.SCSIControllerCount > MaxSCSIControllers {
+			return fmt.Errorf("SCSI controller count can't be more than %d", MaxSCSIControllers)
 		}
 		if opts.VPMemDeviceCount > MaxVPMEMCount {
 			return fmt.Errorf("VPMem device count cannot be greater than %d", MaxVPMEMCount)
@@ -141,10 +144,6 @@ func verifyOptions(ctx context.Context, options interface{}) error {
 			if opts.VPMemSizeBytes%4096 != 0 {
 				return errors.New("VPMemSizeBytes must be a multiple of 4096")
 			}
-		} else {
-			if opts.PreferredRootFSType == PreferredRootFSTypeVHD {
-				return errors.New("PreferredRootFSTypeVHD requires at least one VPMem device")
-			}
 		}
 		if opts.KernelDirect && osversion.Build() < 18286 {
 			return errors.New("KernelDirectBoot is not supported on builds older than 18286")
@@ -160,6 +159,9 @@ func verifyOptions(ctx context.Context, options interface{}) error {
 		if len(opts.LayerFolders) < 2 {
 			return errors.New("at least 2 LayerFolders must be supplied")
 		}
+		if opts.SCSIControllerCount != 1 {
+			return errors.New("exactly 1 SCSI controller is required for WCOW")
+		}
 		if opts.IsClone && !verifyCloneUvmCreateOpts(&opts.TemplateConfig.CreateOpts, opts) {
 			return errors.New("clone configuration doesn't match with template configuration")
 		}
@@ -188,6 +190,7 @@ func newDefaultOptions(id, owner string) *Options {
 		ProcessorCount:        defaultProcessorCount(),
 		FullyPhysicallyBacked: false,
 		NoWritableFileShares:  false,
+		SCSIControllerCount:   1,
 	}
 
 	if opts.Owner == "" {
diff --git a/internal/uvm/create_lcow.go b/internal/uvm/create_lcow.go
index 1211f78ceb..ee42371826 100644
--- a/internal/uvm/create_lcow.go
+++ b/internal/uvm/create_lcow.go
@@ -23,6 +23,7 @@ import (
 	"github.com/Microsoft/hcsshim/internal/logfields"
 	"github.com/Microsoft/hcsshim/internal/oc"
 	"github.com/Microsoft/hcsshim/internal/processorinfo"
+	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
 	"github.com/Microsoft/hcsshim/internal/schemaversion"
 	"github.com/Microsoft/hcsshim/osversion"
 )
@@ -86,7 +87,6 @@ type OptionsLCOW struct {
 	KernelBootOptions       string              // Additional boot options for the kernel
 	EnableGraphicsConsole   bool                // If true, enable a graphics console for the utility VM
 	ConsolePipe             string              // The named pipe path to use for the serial console.  eg \\.\pipe\vmpipe
-	SCSIControllerCount     uint32              // The number of SCSI controllers. Defaults to 1. Currently we only support 0 or 1.
 	UseGuestConnection      bool                // Whether the HCS should connect to the UVM's GCS. Defaults to true
 	ExecCommandLine         string              // The command line to exec from init. Defaults to GCS
 	ForwardStdout           bool                // Whether stdout will be forwarded from the executed program. Defaults to false
@@ -137,7 +137,6 @@ func NewDefaultOptionsLCOW(id, owner string) *OptionsLCOW {
 		KernelBootOptions:       "",
 		EnableGraphicsConsole:   false,
 		ConsolePipe:             "",
-		SCSIControllerCount:     1,
 		UseGuestConnection:      true,
 		ExecCommandLine:         fmt.Sprintf("/bin/gcs -v4 -log-format json -loglevel %s", logrus.StandardLogger().Level.String()),
 		ForwardStdout:           false,
@@ -352,11 +351,11 @@ func makeLCOWVMGSDoc(ctx context.Context, opts *OptionsLCOW, uvm *UtilityVM) (_
 	}
 
 	if uvm.scsiControllerCount > 0 {
-		// TODO: JTERRY75 - this should enumerate scsicount and add an entry per value.
-		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{
-			"0": {
+		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{}
+		for i := 0; i < int(uvm.scsiControllerCount); i++ {
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[i]] = hcsschema.Scsi{
 				Attachments: make(map[string]hcsschema.Attachment),
-			},
+			}
 		}
 	}
 
@@ -537,13 +536,14 @@ func makeLCOWDoc(ctx context.Context, opts *OptionsLCOW, uvm *UtilityVM) (_ *hcs
 	}
 
 	if uvm.scsiControllerCount > 0 {
-		// TODO: JTERRY75 - this should enumerate scsicount and add an entry per value.
-		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{
-			"0": {
+		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{}
+		for i := 0; i < int(uvm.scsiControllerCount); i++ {
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[i]] = hcsschema.Scsi{
 				Attachments: make(map[string]hcsschema.Attachment),
-			},
+			}
 		}
 	}
+
 	if uvm.vpmemMaxCount > 0 {
 		doc.VirtualMachine.Devices.VirtualPMem = &hcsschema.VirtualPMemController{
 			MaximumCount:     uvm.vpmemMaxCount,
@@ -558,48 +558,59 @@ func makeLCOWDoc(ctx context.Context, opts *OptionsLCOW, uvm *UtilityVM) (_ *hcs
 			kernelArgs = "initrd=/" + opts.RootFSFile
 		}
 	case PreferredRootFSTypeVHD:
-		// Support for VPMem VHD(X) booting rather than initrd..
-		kernelArgs = "root=/dev/pmem0 ro rootwait init=/init"
-		imageFormat := "Vhd1"
-		if strings.ToLower(filepath.Ext(opts.RootFSFile)) == "vhdx" {
-			imageFormat = "Vhdx"
-		}
-		doc.VirtualMachine.Devices.VirtualPMem.Devices = map[string]hcsschema.VirtualPMemDevice{
-			"0": {
-				HostPath:    rootfsFullPath,
-				ReadOnly:    true,
-				ImageFormat: imageFormat,
-			},
-		}
-		if uvm.vpmemMultiMapping {
-			pmem := newPackedVPMemDevice()
-			pmem.maxMappedDeviceCount = 1
-
-			st, err := os.Stat(rootfsFullPath)
-			if err != nil {
-				return nil, errors.Wrapf(err, "failed to stat rootfs: %q", rootfsFullPath)
+		if uvm.vpmemMaxCount > 0 {
+			// Support for VPMem VHD(X) booting rather than initrd..
+			kernelArgs = "root=/dev/pmem0 ro rootwait init=/init"
+			imageFormat := "Vhd1"
+			if strings.ToLower(filepath.Ext(opts.RootFSFile)) == "vhdx" {
+				imageFormat = "Vhdx"
 			}
-			devSize := pageAlign(uint64(st.Size()))
-			memReg, err := pmem.Allocate(devSize)
-			if err != nil {
-				return nil, errors.Wrap(err, "failed to allocate memory for rootfs")
+			doc.VirtualMachine.Devices.VirtualPMem.Devices = map[string]hcsschema.VirtualPMemDevice{
+				"0": {
+					HostPath:    rootfsFullPath,
+					ReadOnly:    true,
+					ImageFormat: imageFormat,
+				},
 			}
-			defer func() {
+			if uvm.vpmemMultiMapping {
+				pmem := newPackedVPMemDevice()
+				pmem.maxMappedDeviceCount = 1
+
+				st, err := os.Stat(rootfsFullPath)
 				if err != nil {
-					if err = pmem.Release(memReg); err != nil {
-						log.G(ctx).WithError(err).Debug("failed to release memory region")
-					}
+					return nil, errors.Wrapf(err, "failed to stat rootfs: %q", rootfsFullPath)
 				}
-			}()
+				devSize := pageAlign(uint64(st.Size()))
+				memReg, err := pmem.Allocate(devSize)
+				if err != nil {
+					return nil, errors.Wrap(err, "failed to allocate memory for rootfs")
+				}
+				defer func() {
+					if err != nil {
+						if err = pmem.Release(memReg); err != nil {
+							log.G(ctx).WithError(err).Debug("failed to release memory region")
+						}
+					}
+				}()
 
-			dev := newVPMemMappedDevice(opts.RootFSFile, "/", devSize, memReg)
-			if err := pmem.mapVHDLayer(ctx, dev); err != nil {
-				return nil, errors.Wrapf(err, "failed to save internal state for a multi-mapped rootfs device")
+				dev := newVPMemMappedDevice(opts.RootFSFile, "/", devSize, memReg)
+				if err := pmem.mapVHDLayer(ctx, dev); err != nil {
+					return nil, errors.Wrapf(err, "failed to save internal state for a multi-mapped rootfs device")
+				}
+				uvm.vpmemDevicesMultiMapped[0] = pmem
+			} else {
+				dev := newDefaultVPMemInfo(opts.RootFSFile, "/")
+				uvm.vpmemDevicesDefault[0] = dev
 			}
-			uvm.vpmemDevicesMultiMapped[0] = pmem
 		} else {
-			dev := newDefaultVPMemInfo(opts.RootFSFile, "/")
-			uvm.vpmemDevicesDefault[0] = dev
+			kernelArgs = "root=/dev/sda ro rootwait init=/init"
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"] = hcsschema.Attachment{
+				Type_:    "VirtualDisk",
+				Path:     rootfsFullPath,
+				ReadOnly: true,
+			}
+			uvm.scsiLocations[0][0] = newSCSIMount(uvm, rootfsFullPath, "/", "VirtualDisk", "", 1, 0, 0, true, false)
+
 		}
 	}
 
@@ -737,6 +748,12 @@ func CreateLCOW(ctx context.Context, opts *OptionsLCOW) (_ *UtilityVM, err error
 		}
 	}()
 
+	// vpmemMaxCount has been set to 0 which means we are going to need multiple SCSI controllers
+	// to support lots of layers.
+	if osversion.Build() >= osversion.RS5 && uvm.vpmemMaxCount == 0 {
+		uvm.scsiControllerCount = 4
+	}
+
 	if err = verifyOptions(ctx, opts); err != nil {
 		return nil, errors.Wrap(err, errBadUVMOpts.Error())
 	}
diff --git a/internal/uvm/create_wcow.go b/internal/uvm/create_wcow.go
index 1d083ffda2..4a92fc962d 100644
--- a/internal/uvm/create_wcow.go
+++ b/internal/uvm/create_wcow.go
@@ -17,6 +17,7 @@ import (
 	"github.com/Microsoft/hcsshim/internal/logfields"
 	"github.com/Microsoft/hcsshim/internal/oc"
 	"github.com/Microsoft/hcsshim/internal/processorinfo"
+	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
 	"github.com/Microsoft/hcsshim/internal/schemaversion"
 	"github.com/Microsoft/hcsshim/internal/uvmfolder"
 	"github.com/Microsoft/hcsshim/internal/wclayer"
@@ -249,7 +250,7 @@ func CreateWCOW(ctx context.Context, opts *OptionsWCOW) (_ *UtilityVM, err error
 		id:                      opts.ID,
 		owner:                   opts.Owner,
 		operatingSystem:         "windows",
-		scsiControllerCount:     1,
+		scsiControllerCount:     opts.SCSIControllerCount,
 		vsmbDirShares:           make(map[string]*VSMBShare),
 		vsmbFileShares:          make(map[string]*VSMBShare),
 		vpciDevices:             make(map[VPCIDeviceKey]*VPCIDevice),
@@ -310,21 +311,23 @@ func CreateWCOW(ctx context.Context, opts *OptionsWCOW) (_ *UtilityVM, err error
 			}
 		}
 
-		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{
-			"0": {
-				Attachments: map[string]hcsschema.Attachment{
-					"0": {
-						Path:  scratchPath,
-						Type_: "VirtualDisk",
-					},
-				},
-			},
+		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{}
+		for i := 0; i < int(uvm.scsiControllerCount); i++ {
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[i]] = hcsschema.Scsi{
+				Attachments: make(map[string]hcsschema.Attachment),
+			}
+		}
+
+		doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"] = hcsschema.Attachment{
+
+			Path:  scratchPath,
+			Type_: "VirtualDisk",
 		}
 
 		uvm.scsiLocations[0][0] = newSCSIMount(uvm,
-			doc.VirtualMachine.Devices.Scsi["0"].Attachments["0"].Path,
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"].Path,
 			"",
-			doc.VirtualMachine.Devices.Scsi["0"].Attachments["0"].Type_,
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"].Type_,
 			"",
 			1,
 			0,
diff --git a/internal/uvm/scsi.go b/internal/uvm/scsi.go
index 5cac727387..78d7516ffa 100644
--- a/internal/uvm/scsi.go
+++ b/internal/uvm/scsi.go
@@ -8,7 +8,6 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"strconv"
 	"strings"
 
 	"github.com/Microsoft/go-winio/pkg/security"
@@ -169,8 +168,8 @@ func newSCSIMount(
 // SCSI controllers associated with a utility VM to use.
 // Lock must be held when calling this function
 func (uvm *UtilityVM) allocateSCSISlot(ctx context.Context) (int, int, error) {
-	for controller, luns := range uvm.scsiLocations {
-		for lun, sm := range luns {
+	for controller := 0; controller < int(uvm.scsiControllerCount); controller++ {
+		for lun, sm := range uvm.scsiLocations[controller] {
 			// If sm is nil, we have found an open slot so we allocate a new SCSIMount
 			if sm == nil {
 				return controller, lun, nil
@@ -224,7 +223,7 @@ func (uvm *UtilityVM) RemoveSCSI(ctx context.Context, hostPath string) error {
 
 	scsiModification := &hcsschema.ModifySettingRequest{
 		RequestType:  guestrequest.RequestTypeRemove,
-		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, strconv.Itoa(sm.Controller), sm.LUN),
+		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, guestrequest.ScsiControllerGuids[sm.Controller], sm.LUN),
 	}
 
 	var verity *guestresource.DeviceVerityInfo
@@ -408,11 +407,6 @@ func (uvm *UtilityVM) addSCSIActual(ctx context.Context, addReq *addSCSIRequest)
 		return nil, ErrNoSCSIControllers
 	}
 
-	// Note: Can remove this check post-RS5 if multiple controllers are supported
-	if sm.Controller > 0 {
-		return nil, ErrTooManyAttachments
-	}
-
 	SCSIModification := &hcsschema.ModifySettingRequest{
 		RequestType: guestrequest.RequestTypeAdd,
 		Settings: hcsschema.Attachment{
@@ -421,7 +415,7 @@ func (uvm *UtilityVM) addSCSIActual(ctx context.Context, addReq *addSCSIRequest)
 			ReadOnly:                  addReq.readOnly,
 			ExtensibleVirtualDiskType: addReq.evdType,
 		},
-		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, strconv.Itoa(sm.Controller), sm.LUN),
+		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, guestrequest.ScsiControllerGuids[sm.Controller], sm.LUN),
 	}
 
 	if sm.UVMPath != "" {
@@ -637,7 +631,7 @@ func (sm *SCSIMount) Clone(ctx context.Context, vm *UtilityVM, cd *cloneData) er
 		dstVhdPath string = sm.HostPath
 		err        error
 		dir        string
-		conStr     string = fmt.Sprintf("%d", sm.Controller)
+		conStr     string = guestrequest.ScsiControllerGuids[sm.Controller]
 		lunStr     string = fmt.Sprintf("%d", sm.LUN)
 	)
 
diff --git a/test/cri-containerd/disable_vpmem_test.go b/test/cri-containerd/disable_vpmem_test.go
new file mode 100644
index 0000000000..d40e5f3148
--- /dev/null
+++ b/test/cri-containerd/disable_vpmem_test.go
@@ -0,0 +1,106 @@
+//go:build functional
+// +build functional
+
+package cri_containerd
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/Microsoft/hcsshim/pkg/annotations"
+	runtime "k8s.io/cri-api/pkg/apis/runtime/v1alpha2"
+)
+
+// Use unique names for pods & containers so that if we run this test multiple times in parallel we don't
+// get failures due to same pod/container names.
+func uniqueRef() string {
+	t := time.Now()
+	var b [3]byte
+	// Ignore read failures, just decreases uniqueness
+	rand.Read(b[:])
+	return fmt.Sprintf("%d-%s", t.UnixNano(), base64.URLEncoding.EncodeToString(b[:]))
+}
+
+func Test_70LayerImagesWithNoVPmemForLayers(t *testing.T) {
+	requireFeatures(t, featureLCOW)
+
+	ubuntu70Image := "cplatpublic.azurecr.io/ubuntu70extra:18.04"
+	alpine70Image := "cplatpublic.azurecr.io/alpine70extra:latest"
+	testImages := []string{ubuntu70Image, alpine70Image}
+	pullRequiredLCOWImages(t, []string{imageLcowK8sPause, ubuntu70Image, alpine70Image})
+
+	client := newTestRuntimeClient(t)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	nContainers := 4
+	podID := ""
+	containerIDs := make([]string, nContainers)
+
+	defer cleanupPod(t, client, ctx, &podID)
+	for i := 0; i < nContainers; i++ {
+		defer cleanupContainer(t, client, ctx, &containerIDs[i])
+	}
+
+	sandboxRequest := getRunPodSandboxRequest(
+		t,
+		lcowRuntimeHandler,
+		WithSandboxAnnotations(map[string]string{
+			annotations.VPMemCount: "0",
+		}),
+	)
+	// override pod name
+	sandboxRequest.Config.Metadata.Name = fmt.Sprintf("%s-pod-%s", t.Name(), uniqueRef())
+
+	response, err := client.RunPodSandbox(ctx, sandboxRequest)
+	if err != nil {
+		t.Fatalf("failed RunPodSandbox request with: %v", err)
+	}
+	podID = response.PodSandboxId
+
+	var wg sync.WaitGroup
+	wg.Add(nContainers)
+	for idx := 0; idx < nContainers; idx++ {
+		go func(i int) {
+			defer wg.Done()
+			request := &runtime.CreateContainerRequest{
+				PodSandboxId: podID,
+				Config: &runtime.ContainerConfig{
+					Metadata: &runtime.ContainerMetadata{
+						Name: fmt.Sprintf("%s-container", uniqueRef()),
+					},
+					Image: &runtime.ImageSpec{
+						Image: testImages[i%2],
+					},
+					Command: []string{
+						"/bin/sh",
+						"-c",
+						"while true; do echo 'Hello, World!'; sleep 1; done",
+					},
+				},
+				SandboxConfig: sandboxRequest.Config,
+			}
+
+			containerIDs[i] = createContainer(t, client, ctx, request)
+			startContainer(t, client, ctx, containerIDs[i])
+		}(idx)
+	}
+	wg.Wait()
+
+	for i := 0; i < nContainers; i++ {
+		containerExecReq := &runtime.ExecSyncRequest{
+			ContainerId: containerIDs[i],
+			Cmd:         []string{"ls"},
+			Timeout:     20,
+		}
+		r := execSync(t, client, ctx, containerExecReq)
+		if r.ExitCode != 0 {
+			t.Fatalf("failed to exec inside container, exit code: %d", r.ExitCode)
+		}
+	}
+}
diff --git a/test/vendor/github.com/Microsoft/hcsshim/internal/protocol/guestrequest/types.go b/test/vendor/github.com/Microsoft/hcsshim/internal/protocol/guestrequest/types.go
index 5c3d7111d4..d8d0c20b10 100644
--- a/test/vendor/github.com/Microsoft/hcsshim/internal/protocol/guestrequest/types.go
+++ b/test/vendor/github.com/Microsoft/hcsshim/internal/protocol/guestrequest/types.go
@@ -41,3 +41,16 @@ type RS4NetworkModifyRequest struct {
 	RequestType       RequestType `json:"RequestType,omitempty"`
 	Settings          interface{} `json:"Settings,omitempty"`
 }
+
+var (
+	// V5 GUIDs for SCSI controllers
+	// These GUIDs are created with namespace GUID "d422512d-2bf2-4752-809d-7b82b5fcb1b4"
+	// and index as names. For example, first GUID is created like this:
+	// guid.NewV5("d422512d-2bf2-4752-809d-7b82b5fcb1b4", []byte("0"))
+	ScsiControllerGuids = []string{
+		"df6d0690-79e5-55b6-a5ec-c1e2f77f580a",
+		"0110f83b-de10-5172-a266-78bca56bf50a",
+		"b5d2d8d4-3a75-51bf-945b-3444dc6b8579",
+		"305891a9-b251-5dfe-91a2-c25d9212275b",
+	}
+)
diff --git a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/constants.go b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/constants.go
index 842a8a5e8c..9be9fc4043 100644
--- a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/constants.go
+++ b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/constants.go
@@ -2,6 +2,8 @@ package uvm
 
 import (
 	"errors"
+
+	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
 )
 
 const (
@@ -34,4 +36,7 @@ const (
 var (
 	errNotSupported = errors.New("not supported")
 	errBadUVMOpts   = errors.New("UVM options incorrect")
+
+	// Maximum number of SCSI controllers allowed
+	MaxSCSIControllers = uint32(len(guestrequest.ScsiControllerGuids))
 )
diff --git a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create.go b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create.go
index a3d9fcd4e6..1a08bae535 100644
--- a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create.go
+++ b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create.go
@@ -94,6 +94,9 @@ type Options struct {
 
 	// NoWritableFileShares disables adding any writable vSMB and Plan9 shares to the UVM
 	NoWritableFileShares bool
+
+	// The number of SCSI controllers. Defaults to 1 for WCOW and 4 for LCOW
+	SCSIControllerCount uint32
 }
 
 // compares the create opts used during template creation with the create opts
@@ -131,8 +134,8 @@ func verifyOptions(ctx context.Context, options interface{}) error {
 		if opts.EnableDeferredCommit && !opts.AllowOvercommit {
 			return errors.New("EnableDeferredCommit is not supported on physically backed VMs")
 		}
-		if opts.SCSIControllerCount > 1 {
-			return errors.New("SCSI controller count must be 0 or 1") // Future extension here for up to 4
+		if opts.SCSIControllerCount > MaxSCSIControllers {
+			return fmt.Errorf("SCSI controller count can't be more than %d", MaxSCSIControllers)
 		}
 		if opts.VPMemDeviceCount > MaxVPMEMCount {
 			return fmt.Errorf("VPMem device count cannot be greater than %d", MaxVPMEMCount)
@@ -141,10 +144,6 @@ func verifyOptions(ctx context.Context, options interface{}) error {
 			if opts.VPMemSizeBytes%4096 != 0 {
 				return errors.New("VPMemSizeBytes must be a multiple of 4096")
 			}
-		} else {
-			if opts.PreferredRootFSType == PreferredRootFSTypeVHD {
-				return errors.New("PreferredRootFSTypeVHD requires at least one VPMem device")
-			}
 		}
 		if opts.KernelDirect && osversion.Build() < 18286 {
 			return errors.New("KernelDirectBoot is not supported on builds older than 18286")
@@ -160,6 +159,9 @@ func verifyOptions(ctx context.Context, options interface{}) error {
 		if len(opts.LayerFolders) < 2 {
 			return errors.New("at least 2 LayerFolders must be supplied")
 		}
+		if opts.SCSIControllerCount != 1 {
+			return errors.New("exactly 1 SCSI controller is required for WCOW")
+		}
 		if opts.IsClone && !verifyCloneUvmCreateOpts(&opts.TemplateConfig.CreateOpts, opts) {
 			return errors.New("clone configuration doesn't match with template configuration")
 		}
@@ -188,6 +190,7 @@ func newDefaultOptions(id, owner string) *Options {
 		ProcessorCount:        defaultProcessorCount(),
 		FullyPhysicallyBacked: false,
 		NoWritableFileShares:  false,
+		SCSIControllerCount:   1,
 	}
 
 	if opts.Owner == "" {
diff --git a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_lcow.go b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_lcow.go
index 1211f78ceb..ee42371826 100644
--- a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_lcow.go
+++ b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_lcow.go
@@ -23,6 +23,7 @@ import (
 	"github.com/Microsoft/hcsshim/internal/logfields"
 	"github.com/Microsoft/hcsshim/internal/oc"
 	"github.com/Microsoft/hcsshim/internal/processorinfo"
+	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
 	"github.com/Microsoft/hcsshim/internal/schemaversion"
 	"github.com/Microsoft/hcsshim/osversion"
 )
@@ -86,7 +87,6 @@ type OptionsLCOW struct {
 	KernelBootOptions       string              // Additional boot options for the kernel
 	EnableGraphicsConsole   bool                // If true, enable a graphics console for the utility VM
 	ConsolePipe             string              // The named pipe path to use for the serial console.  eg \\.\pipe\vmpipe
-	SCSIControllerCount     uint32              // The number of SCSI controllers. Defaults to 1. Currently we only support 0 or 1.
 	UseGuestConnection      bool                // Whether the HCS should connect to the UVM's GCS. Defaults to true
 	ExecCommandLine         string              // The command line to exec from init. Defaults to GCS
 	ForwardStdout           bool                // Whether stdout will be forwarded from the executed program. Defaults to false
@@ -137,7 +137,6 @@ func NewDefaultOptionsLCOW(id, owner string) *OptionsLCOW {
 		KernelBootOptions:       "",
 		EnableGraphicsConsole:   false,
 		ConsolePipe:             "",
-		SCSIControllerCount:     1,
 		UseGuestConnection:      true,
 		ExecCommandLine:         fmt.Sprintf("/bin/gcs -v4 -log-format json -loglevel %s", logrus.StandardLogger().Level.String()),
 		ForwardStdout:           false,
@@ -352,11 +351,11 @@ func makeLCOWVMGSDoc(ctx context.Context, opts *OptionsLCOW, uvm *UtilityVM) (_
 	}
 
 	if uvm.scsiControllerCount > 0 {
-		// TODO: JTERRY75 - this should enumerate scsicount and add an entry per value.
-		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{
-			"0": {
+		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{}
+		for i := 0; i < int(uvm.scsiControllerCount); i++ {
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[i]] = hcsschema.Scsi{
 				Attachments: make(map[string]hcsschema.Attachment),
-			},
+			}
 		}
 	}
 
@@ -537,13 +536,14 @@ func makeLCOWDoc(ctx context.Context, opts *OptionsLCOW, uvm *UtilityVM) (_ *hcs
 	}
 
 	if uvm.scsiControllerCount > 0 {
-		// TODO: JTERRY75 - this should enumerate scsicount and add an entry per value.
-		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{
-			"0": {
+		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{}
+		for i := 0; i < int(uvm.scsiControllerCount); i++ {
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[i]] = hcsschema.Scsi{
 				Attachments: make(map[string]hcsschema.Attachment),
-			},
+			}
 		}
 	}
+
 	if uvm.vpmemMaxCount > 0 {
 		doc.VirtualMachine.Devices.VirtualPMem = &hcsschema.VirtualPMemController{
 			MaximumCount:     uvm.vpmemMaxCount,
@@ -558,48 +558,59 @@ func makeLCOWDoc(ctx context.Context, opts *OptionsLCOW, uvm *UtilityVM) (_ *hcs
 			kernelArgs = "initrd=/" + opts.RootFSFile
 		}
 	case PreferredRootFSTypeVHD:
-		// Support for VPMem VHD(X) booting rather than initrd..
-		kernelArgs = "root=/dev/pmem0 ro rootwait init=/init"
-		imageFormat := "Vhd1"
-		if strings.ToLower(filepath.Ext(opts.RootFSFile)) == "vhdx" {
-			imageFormat = "Vhdx"
-		}
-		doc.VirtualMachine.Devices.VirtualPMem.Devices = map[string]hcsschema.VirtualPMemDevice{
-			"0": {
-				HostPath:    rootfsFullPath,
-				ReadOnly:    true,
-				ImageFormat: imageFormat,
-			},
-		}
-		if uvm.vpmemMultiMapping {
-			pmem := newPackedVPMemDevice()
-			pmem.maxMappedDeviceCount = 1
-
-			st, err := os.Stat(rootfsFullPath)
-			if err != nil {
-				return nil, errors.Wrapf(err, "failed to stat rootfs: %q", rootfsFullPath)
+		if uvm.vpmemMaxCount > 0 {
+			// Support for VPMem VHD(X) booting rather than initrd..
+			kernelArgs = "root=/dev/pmem0 ro rootwait init=/init"
+			imageFormat := "Vhd1"
+			if strings.ToLower(filepath.Ext(opts.RootFSFile)) == "vhdx" {
+				imageFormat = "Vhdx"
 			}
-			devSize := pageAlign(uint64(st.Size()))
-			memReg, err := pmem.Allocate(devSize)
-			if err != nil {
-				return nil, errors.Wrap(err, "failed to allocate memory for rootfs")
+			doc.VirtualMachine.Devices.VirtualPMem.Devices = map[string]hcsschema.VirtualPMemDevice{
+				"0": {
+					HostPath:    rootfsFullPath,
+					ReadOnly:    true,
+					ImageFormat: imageFormat,
+				},
 			}
-			defer func() {
+			if uvm.vpmemMultiMapping {
+				pmem := newPackedVPMemDevice()
+				pmem.maxMappedDeviceCount = 1
+
+				st, err := os.Stat(rootfsFullPath)
 				if err != nil {
-					if err = pmem.Release(memReg); err != nil {
-						log.G(ctx).WithError(err).Debug("failed to release memory region")
-					}
+					return nil, errors.Wrapf(err, "failed to stat rootfs: %q", rootfsFullPath)
 				}
-			}()
+				devSize := pageAlign(uint64(st.Size()))
+				memReg, err := pmem.Allocate(devSize)
+				if err != nil {
+					return nil, errors.Wrap(err, "failed to allocate memory for rootfs")
+				}
+				defer func() {
+					if err != nil {
+						if err = pmem.Release(memReg); err != nil {
+							log.G(ctx).WithError(err).Debug("failed to release memory region")
+						}
+					}
+				}()
 
-			dev := newVPMemMappedDevice(opts.RootFSFile, "/", devSize, memReg)
-			if err := pmem.mapVHDLayer(ctx, dev); err != nil {
-				return nil, errors.Wrapf(err, "failed to save internal state for a multi-mapped rootfs device")
+				dev := newVPMemMappedDevice(opts.RootFSFile, "/", devSize, memReg)
+				if err := pmem.mapVHDLayer(ctx, dev); err != nil {
+					return nil, errors.Wrapf(err, "failed to save internal state for a multi-mapped rootfs device")
+				}
+				uvm.vpmemDevicesMultiMapped[0] = pmem
+			} else {
+				dev := newDefaultVPMemInfo(opts.RootFSFile, "/")
+				uvm.vpmemDevicesDefault[0] = dev
 			}
-			uvm.vpmemDevicesMultiMapped[0] = pmem
 		} else {
-			dev := newDefaultVPMemInfo(opts.RootFSFile, "/")
-			uvm.vpmemDevicesDefault[0] = dev
+			kernelArgs = "root=/dev/sda ro rootwait init=/init"
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"] = hcsschema.Attachment{
+				Type_:    "VirtualDisk",
+				Path:     rootfsFullPath,
+				ReadOnly: true,
+			}
+			uvm.scsiLocations[0][0] = newSCSIMount(uvm, rootfsFullPath, "/", "VirtualDisk", "", 1, 0, 0, true, false)
+
 		}
 	}
 
@@ -737,6 +748,12 @@ func CreateLCOW(ctx context.Context, opts *OptionsLCOW) (_ *UtilityVM, err error
 		}
 	}()
 
+	// vpmemMaxCount has been set to 0 which means we are going to need multiple SCSI controllers
+	// to support lots of layers.
+	if osversion.Build() >= osversion.RS5 && uvm.vpmemMaxCount == 0 {
+		uvm.scsiControllerCount = 4
+	}
+
 	if err = verifyOptions(ctx, opts); err != nil {
 		return nil, errors.Wrap(err, errBadUVMOpts.Error())
 	}
diff --git a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_wcow.go b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_wcow.go
index 1d083ffda2..4a92fc962d 100644
--- a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_wcow.go
+++ b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/create_wcow.go
@@ -17,6 +17,7 @@ import (
 	"github.com/Microsoft/hcsshim/internal/logfields"
 	"github.com/Microsoft/hcsshim/internal/oc"
 	"github.com/Microsoft/hcsshim/internal/processorinfo"
+	"github.com/Microsoft/hcsshim/internal/protocol/guestrequest"
 	"github.com/Microsoft/hcsshim/internal/schemaversion"
 	"github.com/Microsoft/hcsshim/internal/uvmfolder"
 	"github.com/Microsoft/hcsshim/internal/wclayer"
@@ -249,7 +250,7 @@ func CreateWCOW(ctx context.Context, opts *OptionsWCOW) (_ *UtilityVM, err error
 		id:                      opts.ID,
 		owner:                   opts.Owner,
 		operatingSystem:         "windows",
-		scsiControllerCount:     1,
+		scsiControllerCount:     opts.SCSIControllerCount,
 		vsmbDirShares:           make(map[string]*VSMBShare),
 		vsmbFileShares:          make(map[string]*VSMBShare),
 		vpciDevices:             make(map[VPCIDeviceKey]*VPCIDevice),
@@ -310,21 +311,23 @@ func CreateWCOW(ctx context.Context, opts *OptionsWCOW) (_ *UtilityVM, err error
 			}
 		}
 
-		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{
-			"0": {
-				Attachments: map[string]hcsschema.Attachment{
-					"0": {
-						Path:  scratchPath,
-						Type_: "VirtualDisk",
-					},
-				},
-			},
+		doc.VirtualMachine.Devices.Scsi = map[string]hcsschema.Scsi{}
+		for i := 0; i < int(uvm.scsiControllerCount); i++ {
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[i]] = hcsschema.Scsi{
+				Attachments: make(map[string]hcsschema.Attachment),
+			}
+		}
+
+		doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"] = hcsschema.Attachment{
+
+			Path:  scratchPath,
+			Type_: "VirtualDisk",
 		}
 
 		uvm.scsiLocations[0][0] = newSCSIMount(uvm,
-			doc.VirtualMachine.Devices.Scsi["0"].Attachments["0"].Path,
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"].Path,
 			"",
-			doc.VirtualMachine.Devices.Scsi["0"].Attachments["0"].Type_,
+			doc.VirtualMachine.Devices.Scsi[guestrequest.ScsiControllerGuids[0]].Attachments["0"].Type_,
 			"",
 			1,
 			0,
diff --git a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/scsi.go b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/scsi.go
index 5cac727387..78d7516ffa 100644
--- a/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/scsi.go
+++ b/test/vendor/github.com/Microsoft/hcsshim/internal/uvm/scsi.go
@@ -8,7 +8,6 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"strconv"
 	"strings"
 
 	"github.com/Microsoft/go-winio/pkg/security"
@@ -169,8 +168,8 @@ func newSCSIMount(
 // SCSI controllers associated with a utility VM to use.
 // Lock must be held when calling this function
 func (uvm *UtilityVM) allocateSCSISlot(ctx context.Context) (int, int, error) {
-	for controller, luns := range uvm.scsiLocations {
-		for lun, sm := range luns {
+	for controller := 0; controller < int(uvm.scsiControllerCount); controller++ {
+		for lun, sm := range uvm.scsiLocations[controller] {
 			// If sm is nil, we have found an open slot so we allocate a new SCSIMount
 			if sm == nil {
 				return controller, lun, nil
@@ -224,7 +223,7 @@ func (uvm *UtilityVM) RemoveSCSI(ctx context.Context, hostPath string) error {
 
 	scsiModification := &hcsschema.ModifySettingRequest{
 		RequestType:  guestrequest.RequestTypeRemove,
-		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, strconv.Itoa(sm.Controller), sm.LUN),
+		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, guestrequest.ScsiControllerGuids[sm.Controller], sm.LUN),
 	}
 
 	var verity *guestresource.DeviceVerityInfo
@@ -408,11 +407,6 @@ func (uvm *UtilityVM) addSCSIActual(ctx context.Context, addReq *addSCSIRequest)
 		return nil, ErrNoSCSIControllers
 	}
 
-	// Note: Can remove this check post-RS5 if multiple controllers are supported
-	if sm.Controller > 0 {
-		return nil, ErrTooManyAttachments
-	}
-
 	SCSIModification := &hcsschema.ModifySettingRequest{
 		RequestType: guestrequest.RequestTypeAdd,
 		Settings: hcsschema.Attachment{
@@ -421,7 +415,7 @@ func (uvm *UtilityVM) addSCSIActual(ctx context.Context, addReq *addSCSIRequest)
 			ReadOnly:                  addReq.readOnly,
 			ExtensibleVirtualDiskType: addReq.evdType,
 		},
-		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, strconv.Itoa(sm.Controller), sm.LUN),
+		ResourcePath: fmt.Sprintf(resourcepaths.SCSIResourceFormat, guestrequest.ScsiControllerGuids[sm.Controller], sm.LUN),
 	}
 
 	if sm.UVMPath != "" {
@@ -637,7 +631,7 @@ func (sm *SCSIMount) Clone(ctx context.Context, vm *UtilityVM, cd *cloneData) er
 		dstVhdPath string = sm.HostPath
 		err        error
 		dir        string
-		conStr     string = fmt.Sprintf("%d", sm.Controller)
+		conStr     string = guestrequest.ScsiControllerGuids[sm.Controller]
 		lunStr     string = fmt.Sprintf("%d", sm.LUN)
 	)