In testing Windows 8.1 deployment to Surface Pro 2 devices, via PXE and the genuine Microsoft Surface Ethernet Adapter, I came up against long delays during OSD, with the device stuck “Getting Ready” for 30 minutes plus.
Eventually the Task Sequence progress UI appeared and I was able to get access to the Command Line, sure enough there was no ethernet adapter.
For some reason this is completely missing from the October 2013 Driver Pack. For now I have copied the driver from the original Surface Pro driver pack, which resolves the OSD issues.