diff --git a/config.go b/config.go
index 37a2bc345..d086d2d58 100644
--- a/config.go
+++ b/config.go
@@ -14,7 +14,10 @@ import (
 
 // Moby is the type of a Moby config file
 type Moby struct {
-	Kernel string
+	Kernel struct {
+		Image   string
+		Cmdline string
+	}
 	Init   string
 	System []MobyImage
 	Daemon []MobyImage
diff --git a/main.go b/main.go
index 33f92e677..9ef5d9dfc 100644
--- a/main.go
+++ b/main.go
@@ -4,11 +4,11 @@ import (
 	"archive/tar"
 	"bytes"
 	"errors"
+	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"log"
-	"os"
 	"os/exec"
 	"path/filepath"
 
@@ -129,17 +129,7 @@ func containersInitrd(containers []*bytes.Buffer) (*bytes.Buffer, error) {
 	return w, nil
 }
 
-func build(configfile string) {
-	config, err := ioutil.ReadFile(configfile)
-	if err != nil {
-		log.Fatalf("Cannot open config file: %v", err)
-	}
-
-	m, err := NewConfig(config)
-	if err != nil {
-		log.Fatalf("Invalid config: %v", err)
-	}
-
+func build(m *Moby) {
 	containers := []*bytes.Buffer{}
 
 	// get kernel bzImage and initrd tarball from container
@@ -148,7 +138,7 @@ func build(configfile string) {
 		bzimageName = "bzImage"
 		ktarName    = "kernel.tar"
 	)
-	out, err := dockerRun(m.Kernel, "tar", "cf", "-", bzimageName, ktarName)
+	out, err := dockerRun(m.Kernel.Image, "tar", "cf", "-", bzimageName, ktarName)
 	if err != nil {
 		log.Fatalf("Failed to extract kernel image and tarball: %v", err)
 	}
@@ -211,11 +201,34 @@ func build(configfile string) {
 	}
 }
 
-var conf = "moby.yaml"
+var (
+	conf    string
+	cmdline bool
+)
 
 func main() {
-	if len(os.Args) >= 2 {
-		conf = os.Args[1]
+	flag.BoolVar(&cmdline, "cmdline", false, "Print the kernel command line and exit")
+	flag.Parse()
+
+	conf = "moby.yaml"
+	if len(flag.Args()) > 0 {
+		conf = flag.Args()[0]
 	}
-	build(conf)
+
+	config, err := ioutil.ReadFile(conf)
+	if err != nil {
+		log.Fatalf("Cannot open config file: %v", err)
+	}
+
+	m, err := NewConfig(config)
+	if err != nil {
+		log.Fatalf("Invalid config: %v", err)
+	}
+
+	if cmdline {
+		fmt.Printf("%s\n", m.Kernel.Cmdline)
+		return
+	}
+
+	build(m)
 }
diff --git a/output.go b/output.go
index 34f8e92c5..95f4cdb8c 100644
--- a/output.go
+++ b/output.go
@@ -9,8 +9,8 @@ import (
 )
 
 const (
-	bios = "mobylinux/mkimage-iso-bios:6b3ef6d6bdcc5fdf2ee683febac99533c2268c89@sha256:2484146c4dfbd2eee83d9dd3adf84d9232e5dd739d8762275dcd50bf60a529c6"
-	efi  = "mobylinux/mkimage-iso-efi:40f35270037dae95584324427e56f829756ff145@sha256:ae5b37ae560a5e030342f3d493d4ad611f2694bcd54eba86bf42ca069da986a7"
+	bios = "mobylinux/mkimage-iso-bios:489b1f054a77a8f379d0bfc6cd91639b4db6b67c@sha256:0f058951aac4367d132682aa19eeb5cdcb05600a5d51fe5d0fcbd97b03ae4f87"
+	efi  = "mobylinux/mkimage-iso-efi:b210c58e096e53082d35b28fa2b52dba6ae200c8@sha256:10c2789bf5fbd27c35c5fe2f3b97f75a7108bbde389d0f5ed750e3e2dae95376"
 )
 
 func outputs(m *Moby, base string, bzimage []byte, initrd []byte) error {
@@ -22,12 +22,12 @@ func outputs(m *Moby, base string, bzimage []byte, initrd []byte) error {
 				return fmt.Errorf("Error writing %s output: %v", o.Format, err)
 			}
 		case "iso-bios":
-			err := outputISO(bios, base+".iso", bzimage, initrd)
+			err := outputISO(bios, base+".iso", bzimage, initrd, m.Kernel.Cmdline)
 			if err != nil {
 				return fmt.Errorf("Error writing %s output: %v", o.Format, err)
 			}
 		case "iso-efi":
-			err := outputISO(efi, base+"-efi.iso", bzimage, initrd)
+			err := outputISO(efi, base+"-efi.iso", bzimage, initrd, m.Kernel.Cmdline)
 			if err != nil {
 				return fmt.Errorf("Error writing %s output: %v", o.Format, err)
 			}
@@ -41,7 +41,7 @@ func outputs(m *Moby, base string, bzimage []byte, initrd []byte) error {
 }
 
 // TODO add kernel command line
-func outputISO(image, filename string, bzimage []byte, initrd []byte) error {
+func outputISO(image, filename string, bzimage []byte, initrd []byte, args ...string) error {
 	// first build the input tarball from kernel and initrd
 	buf := new(bytes.Buffer)
 	tw := tar.NewWriter(buf)
@@ -75,7 +75,7 @@ func outputISO(image, filename string, bzimage []byte, initrd []byte) error {
 	if err != nil {
 		return err
 	}
-	iso, err := dockerRunInput(buf, image)
+	iso, err := dockerRunInput(buf, append([]string{image}, args...)...)
 	if err != nil {
 		return err
 	}