@@ -527,11 +527,9 @@ func (b *Builder) create() (string, error) {

 	b.tmpContainers[c.ID] = struct{}{}

 	fmt.Fprintf(b.Stdout, " ---> Running in %s\n", stringid.TruncateID(c.ID))

-	if len(config.Cmd) > 0 {

-		// override the entry point that may have been picked up from the base image

-		if err := b.docker.ContainerUpdateCmdOnBuild(c.ID, config.Cmd); err != nil {

-			return "", err

-		}

+	// override the entry point that may have been picked up from the base image

+	if err := b.docker.ContainerUpdateCmdOnBuild(c.ID, config.Cmd); err != nil {

+		return "", err

 	}

 	return c.ID, nil

@@ -25,6 +25,9 @@ func (daemon *Daemon) ContainerUpdate(name string, hostConfig *container.HostCon

 // ContainerUpdateCmdOnBuild updates Path and Args for the container with ID cID.

 func (daemon *Daemon) ContainerUpdateCmdOnBuild(cID string, cmd []string) error {

+	if len(cmd) == 0 {

+		return nil

+	}

 	c, err := daemon.GetContainer(cID)

 	if err != nil {

 		return err

@@ -171,7 +171,7 @@ func TestGetRemoteImageJSON(t *testing.T) {

 		t.Fatal(err)

 	}

 	assertEqual(t, size, int64(154), "Expected size 154")

-	if len(json) <= 0 {

+	if len(json) == 0 {

 		t.Fatal("Expected non-empty json")

 	}