diff --git a/projects/demo/etcd/infrakit.json b/projects/demo/etcd/infrakit.json
index 0d7cef887..b9b83e274 100644
--- a/projects/demo/etcd/infrakit.json
+++ b/projects/demo/etcd/infrakit.json
@@ -13,7 +13,7 @@
         "Instance": {
             "Plugin": "instance-hyperkit",
             "Properties": {
-                "Moby": "etcd",
+                "kernel+initrd": "etcd",
                 "Disk" : 1024,
                 "CPUs" : 1,
                 "Memory" : 1024
diff --git a/src/cmd/infrakit-instance-hyperkit/hyperkit.json b/src/cmd/infrakit-instance-hyperkit/hyperkit.json
index 8521611b9..ef158bbf1 100644
--- a/src/cmd/infrakit-instance-hyperkit/hyperkit.json
+++ b/src/cmd/infrakit-instance-hyperkit/hyperkit.json
@@ -7,7 +7,8 @@
         "Instance": {
             "Plugin": "instance-hyperkit",
             "Properties": {
-                "Moby": "../../moby",
+                "_comment" : "kernel+initrd specifies the prefix as in <prefix>-bzImage and <prefix>-initrd.img",
+                "kernel+initrd": "linux",
                 "Disk" : 512,
                 "CPUs" : 2,
                 "Memory" : 1024
diff --git a/src/cmd/infrakit-instance-hyperkit/instance.go b/src/cmd/infrakit-instance-hyperkit/instance.go
index 79039a129..46a4bb3b8 100644
--- a/src/cmd/infrakit-instance-hyperkit/instance.go
+++ b/src/cmd/infrakit-instance-hyperkit/instance.go
@@ -9,11 +9,10 @@ import (
 	"path"
 
 	log "github.com/Sirupsen/logrus"
-
 	"github.com/docker/hyperkit/go"
-
 	"github.com/docker/infrakit/pkg/spi/instance"
 	"github.com/docker/infrakit/pkg/types"
+	"github.com/rneugeba/iso9660wrap"
 )
 
 // NewHyperKitPlugin creates an instance plugin for hyperkit.
@@ -55,8 +54,8 @@ func (p hyperkitPlugin) Provision(spec instance.Spec) (*instance.ID, error) {
 		}
 	}
 
-	if properties["Moby"] == nil {
-		return nil, errors.New("Property 'Moby' must be set")
+	if properties["kernel+initrd"] == nil {
+		return nil, errors.New("Property 'kernel+initrd' must be set")
 	}
 	if properties["CPUs"] == nil {
 		properties["CPUs"] = 1
@@ -98,28 +97,39 @@ func (p hyperkitPlugin) Provision(spec instance.Spec) (*instance.ID, error) {
 		// so it persists across reboots.
 		if diskSize != 0 {
 			diskImage = path.Join(p.DiskDir, logicalID+".img")
-			// Make sure the directory exists
-			err = os.MkdirAll(p.DiskDir, 0755)
-			if err != nil {
-				return nil, err
-			}
 		}
 	}
+
+	isoImage := ""
+	if spec.Init != "" {
+		isoImage = path.Join(instanceDir, "data.iso")
+		outfh, err := os.OpenFile(isoImage, os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			log.Fatalf("Cannot create user data ISO: %s", err)
+		}
+		err = iso9660wrap.WriteBuffer(outfh, []byte(spec.Init), "config")
+		if err != nil {
+			log.Fatalf("Cannot write user data ISO: %s", err)
+		}
+		outfh.Close()
+	}
+
 	log.Infof("[%s] LogicalID: %s", id, logicalID)
 	log.Debugf("[%s] UUID: %s", id, uuidStr)
 
 	// Start a HyperKit instance
-	h, err := hyperkit.New(p.HyperKit, instanceDir, p.VPNKitSock, diskImage)
+	h, err := hyperkit.New(p.HyperKit, p.VPNKitSock, instanceDir)
 	if err != nil {
 		return nil, err
 	}
-	h.Kernel = properties["Moby"].(string) + "-bzImage"
-	h.Initrd = properties["Moby"].(string) + "-initrd.img"
+	h.Kernel = properties["kernel+initrd"].(string) + "-bzImage"
+	h.Initrd = properties["kernel+initrd"].(string) + "-initrd.img"
+	h.UUID = uuidStr
+	h.DiskImage = diskImage
+	h.ISOImage = isoImage
 	h.CPUs = int(properties["CPUs"].(float64))
 	h.Memory = int(properties["Memory"].(float64))
 	h.DiskSize = diskSize
-	h.UUID = uuidStr
-	h.UserData = spec.Init
 	h.Console = hyperkit.ConsoleFile
 	log.Infof("[%s] Booting: %s/%s", id, h.Kernel, h.Initrd)
 	log.Infof("[%s] %d CPUs, %dMB Memory, %dMB Disk (%s)", id, h.CPUs, h.Memory, h.DiskSize, h.DiskImage)
diff --git a/src/cmd/moby/run_hyperkit.go b/src/cmd/moby/run_hyperkit.go
index 12faea39d..c3d29b1b2 100644
--- a/src/cmd/moby/run_hyperkit.go
+++ b/src/cmd/moby/run_hyperkit.go
@@ -86,18 +86,19 @@ func runHyperKit(args []string) {
 		*disk = prefix + "-disk.img"
 	}
 
-	h, err := hyperkit.New(*hyperkitPath, "", "auto", *disk)
+	h, err := hyperkit.New(*hyperkitPath, "auto", "")
 	if err != nil {
 		log.Fatalln("Error creating hyperkit: ", err)
 	}
 
 	h.Kernel = prefix + "-bzImage"
 	h.Initrd = prefix + "-initrd.img"
+	h.UUID = uuidStr
+	h.DiskImage = *disk
 	h.ISOImage = isoPath
 	h.CPUs = *cpus
 	h.Memory = *mem
 	h.DiskSize = *diskSz
-	h.UUID = uuidStr
 
 	err = h.Run(string(cmdline))
 	if err != nil {
diff --git a/vendor.conf b/vendor.conf
index 3bf35ba7a..f0b7863f5 100644
--- a/vendor.conf
+++ b/vendor.conf
@@ -9,10 +9,10 @@ github.com/docker/distribution 07f32ac1831ed0fc71960b7da5d6bb83cb6881b5
 github.com/docker/engine-api cf82c64276ebc2501e72b241f9fdc1e21e421743
 github.com/docker/go-connections e15c02316c12de00874640cd76311849de2aeed5
 github.com/docker/go-units 651fc226e7441360384da338d0fd37f2440ffbe3
-github.com/docker/hyperkit/go 89b0a4a88ec340c756a6bd14af57e26f69d29d09
+github.com/docker/hyperkit c49c076a1b24883c61f5cfbec7943b2e16ad7c5a
 github.com/docker/infrakit cb420e3e50ea60afe58538b1d3cab1cb14059433
 github.com/ghodss/yaml 0ca9ea5df5451ffdf184b4428c902747c2c11cd7
-github.com/golang/protobuf/proto c9c7427a2a70d2eb3bafa0ab2dc163e45f143317
+github.com/golang/protobuf c9c7427a2a70d2eb3bafa0ab2dc163e45f143317
 github.com/googleapis/gax-go 8c5154c0fe5bf18cf649634d4c6df50897a32751
 github.com/gorilla/context 08b5f424b9271eedf6f9f0ce86cb9396ed337a42
 github.com/gorilla/mux 599cba5e7b6137d46ddf58fb1765f5d928e69604
@@ -31,7 +31,7 @@ github.com/spf13/pflag 9ff6c6923cfffbcd502984b8e0c80539a94968b7
 github.com/surma/gocpio fcb68777e7dc4ea43ffce871b552c0d073c17495
 github.com/vaughan0/go-ini a98ad7ee00ec53921f08832bc06ecf7fd600e6a1
 golang.org/x/crypto 573951cbe80bb6352881271bb276f48749eab6f4
-golang.org/x/net/context a6577fac2d73be281a500b310739095313165611
+golang.org/x/net a6577fac2d73be281a500b310739095313165611
 golang.org/x/oauth2 1611bb46e67abc64a71ecc5c3ae67f1cbbc2b921
 golang.org/x/sys 99f16d856c9836c42d24e7ab64ea72916925fa97
 golang.org/x/text a263ba8
diff --git a/vendor/github.com/docker/hyperkit/go/hyperkit.go b/vendor/github.com/docker/hyperkit/go/hyperkit.go
index f79ff94b1..7f43448ca 100644
--- a/vendor/github.com/docker/hyperkit/go/hyperkit.go
+++ b/vendor/github.com/docker/hyperkit/go/hyperkit.go
@@ -31,12 +31,12 @@ import (
 	"os"
 	"os/exec"
 	"os/user"
+	"path"
 	"path/filepath"
 	"strconv"
 	"strings"
 
 	"github.com/mitchellh/go-ps"
-	"github.com/rneugeba/iso9660wrap"
 )
 
 const (
@@ -94,10 +94,6 @@ type HyperKit struct {
 	// connected to. ConsoleStdio and ConsoleFile are supported.
 	Console int `json:"console"`
 
-	// UserData, if non empty, will be added to a ISO under the
-	// filename `config` and passed to the VM.
-	UserData string `json:"user_data"`
-
 	// Below here are internal members, but they are exported so
 	// that they are written to the state json file, if configured.
 
@@ -118,7 +114,7 @@ type HyperKit struct {
 // - If vpnkitsock is empty no networking is configured. If it is set
 //   to "auto" it tries to re-use the Docker for Mac VPNKit connection.
 // - If statedir is "" no state is written to disk.
-func New(hyperkit, statedir, vpnkitsock, diskimage string) (*HyperKit, error) {
+func New(hyperkit, vpnkitsock, statedir string) (*HyperKit, error) {
 	h := HyperKit{}
 	var err error
 
@@ -131,13 +127,11 @@ func New(hyperkit, statedir, vpnkitsock, diskimage string) (*HyperKit, error) {
 	if err != nil {
 		return nil, err
 	}
-	h.DiskImage = diskimage
 
 	h.CPUs = defaultCPUs
 	h.Memory = defaultMemory
 
 	h.Console = ConsoleStdio
-	h.UserData = ""
 
 	return &h, nil
 }
@@ -199,9 +193,6 @@ func (h *HyperKit) execute(cmdline string) error {
 	if h.Console == ConsoleFile && h.StateDir == "" {
 		return fmt.Errorf("If ConsoleFile is set, StateDir must be specified")
 	}
-	if h.UserData != "" && h.ISOImage != "" {
-		return fmt.Errorf("If UserData is supplied, ISOImage must not be set")
-	}
 	if h.ISOImage != "" {
 		if _, err = os.Stat(h.ISOImage); os.IsNotExist(err) {
 			return fmt.Errorf("ISO %s does not exist", h.ISOImage)
@@ -210,9 +201,6 @@ func (h *HyperKit) execute(cmdline string) error {
 	if h.VSock && h.StateDir == "" {
 		return fmt.Errorf("If virtio-sockets are enabled, StateDir must be specified")
 	}
-	if h.UserData != "" && h.StateDir == "" {
-		return fmt.Errorf("If UserData is supplied, StateDir must be specified")
-	}
 	if _, err = os.Stat(h.Kernel); os.IsNotExist(err) {
 		return fmt.Errorf("Kernel %s does not exist", h.Kernel)
 	}
@@ -241,12 +229,6 @@ func (h *HyperKit) execute(cmdline string) error {
 			}
 		}
 	}
-	if h.UserData != "" {
-		h.ISOImage, err = createUserDataISO(h.StateDir, h.UserData)
-		if err != nil {
-			return err
-		}
-	}
 
 	// Run
 	h.buildArgs(cmdline)
@@ -331,6 +313,13 @@ func (h *HyperKit) String() string {
 
 // CreateDiskImage creates a empty file suitable for use as a disk image for a hyperkit VM.
 func CreateDiskImage(location string, sizeMB int) error {
+	diskDir := path.Dir(location)
+	if diskDir != "." {
+		if err := os.MkdirAll(diskDir, 0755); err != nil {
+			return err
+		}
+	}
+
 	f, err := os.Create(location)
 	if err != nil {
 		return err
@@ -446,6 +435,9 @@ func (h *HyperKit) execHyperKit() error {
 		if err != nil {
 			return err
 		}
+	} else {
+		// Make sure we reap the child when it exits
+		go cmd.Wait()
 	}
 	return nil
 }
@@ -478,31 +470,6 @@ func stream(r io.ReadCloser, dest chan<- string) {
 	}()
 }
 
-// Create a ISO with Userdata in the specified directory
-func createUserDataISO(dir string, init string) (string, error) {
-	cfgName := filepath.Join(dir, "config")
-	isoName := cfgName + ".iso"
-
-	if err := ioutil.WriteFile(cfgName, []byte(init), 0644); err != nil {
-		return "", err
-	}
-
-	outfh, err := os.OpenFile(isoName, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0644)
-	if err != nil {
-		return "", err
-	}
-	infh, err := os.Open(cfgName)
-	if err != nil {
-		return "", err
-	}
-	err = iso9660wrap.WriteFile(outfh, infh)
-	if err != nil {
-		return "", err
-	}
-
-	return isoName, nil
-}
-
 // checkHyperKit tries to find and/or validate the path of hyperkit
 func checkHyperKit(hyperkit string) (string, error) {
 	if hyperkit != "" {