Can not querying inherited type properties in EF TPH

Question

Work on asp.net mvc5 with ef version 6.1.3 and Unity repository .Say there is a model with a base type of SmartDevice and three derived types of SmartRainbow, SmartRouter, SmartSwitch. Like bellow:

private readonly IRepositoryAsync<SmartDevice> _smartDeviceRepository;

constructor has bellow syntax

_smartDeviceRepository = unitOfWork.RepositoryAsync<SmartDevice>();

SmartDevice

 public class SmartDevice : Entity
    {
        #region Primitive Properties
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int DeviceId { get; set; }

        public DeviceType DeviceType { get; set; }
        #endregion



        #region  Navigation Properties

        public virtual ICollection<DeviceStatus> DeviceStatus { get; set; }

        #endregion
    }

SmartSwitch

  public class SmartSwitch : SmartDevice
    {
        #region  Navigation Properties      
        public virtual ICollection<Channel> Channels { get; set; }              
        #endregion
    }

SmartRainbow

 public class SmartRainbow : SmartDevice
    {
        #region  Navigation Properties

        public virtual ICollection<RgbwStatus> RgbwStatuses { get; set; }

        #endregion
    }

By querying SmartDevice I get all entities my syntax is bellow:

var temp = _smartDeviceRepository.Query().Select().ToList();

problem is through every entity of above result will be of type SmartRainbow or SmartRouter or SmartSwitch I can not load any single inherited type properties and navigation propreties.

Using the bellow syntax I failed to load the navigation property

var temp = _smartDeviceRepository.Query().Select().OfType<SmartSwitch>().ToList(); 

• Can not load SmartSwitch property Channels?
• Can not use include after the OfType method?
• Why can not have include after the OfType?