This script for MDT/SCCM demonstrate how to reboot to the same Task Séquence step wether you are on WinPE or Windows.

TestReboot.wsf

<job id="BIOSCheck">
	<script language="VBScript" src="ZTIUtility.vbs"/>
	<script language="VBScript">

		Option Explicit
		RunNewInstance

		Class TestReboot

			Function Main

				oLogging.CreateEntry "@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@" , LogTypeInfo
			
				If oEnvironment.Exists("RebootCount") then 
					oEnvironment.Item("RebootCount") = oEnvironment.Item("RebootCount") + 1
				Else
					oEnvironment.Item("RebootCount") = 1	
				End If
				
				oLogging.CreateEntry "Preparing to reboot for the " & oEnvironment.Item("RebootCount") & " Time" , LogTypeInfo

				oUtility.SafeSleep 15000
				
				If oEnvironment.Item("RebootCount") <= 3 then
				
					If oEnvironment.Item("OSVersion") = "WinPE" Then
						oEnvironment.Item("SMSTSRebootRequested") = "WinPE"
					Else
						oEnvironment.Item("SMSTSRebootRequested") = "true"
					End If
					
					oEnvironment.Item("SMSTSRetryRequested") = "true"
				
					oLogging.CreateEntry "Reboot intitated, quit" , LogTypeInfo
				Else
					oLogging.CreateEntry "Looping Out of reboot, continuing TS execution!" , LogTypeInfo
				End If 	
				oLogging.CreateEntry "@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@" , LogTypeInfo

				Main = SUCCESS

			End Function

		End class

	</script>
</job>