func resource_aws_instance_update(
	s *terraform.ResourceState,
	d *terraform.ResourceDiff,
	meta interface{}) (*terraform.ResourceState, error) {
	p := meta.(*ResourceProvider)
	ec2conn := p.ec2conn
	rs := s.MergeDiff(d)

	modify := false
	opts := new(ec2.ModifyInstance)

	if attr, ok := d.Attributes["source_dest_check"]; ok {
		modify = true
		opts.SourceDestCheck = attr.New != "" && attr.New != "false"
		opts.SetSourceDestCheck = true
		rs.Attributes["source_dest_check"] = strconv.FormatBool(
			opts.SourceDestCheck)
	}

	if modify {
		log.Printf("[INFO] Modifing instance %s: %#v", s.ID, opts)
		if _, err := ec2conn.ModifyInstance(s.ID, opts); err != nil {
			return s, err
		}

		// TODO(mitchellh): wait for the attributes we modified to
		// persist the change...
	}

	return rs, nil
}
func resourceAwsInstanceUpdate(d *schema.ResourceData, meta interface{}) error {
	p := meta.(*ResourceProvider)
	ec2conn := p.ec2conn

	modify := false
	opts := new(ec2.ModifyInstance)

	if v, ok := d.GetOk("source_dest_check"); ok {
		opts.SourceDestCheck = v.(bool)
		opts.SetSourceDestCheck = true
		modify = true
	}

	if modify {
		log.Printf("[INFO] Modifing instance %s: %#v", d.Id(), opts)
		if _, err := ec2conn.ModifyInstance(d.Id(), opts); err != nil {
			return err
		}

		// TODO(mitchellh): wait for the attributes we modified to
		// persist the change...
	}

	return nil
}