I have the same problem!
I have a vPro lab with SCCM SP1 and a Dell Optiplex 755 client, with 3.2.1 MEBx version, the client is provisioned without SCCM agent, but when y try to power on,off,restart nothing happens!
The OOB console try to connect but appears as disconnected.
Were you able to resolve it?
Help me, please?