It is possible to access the Windows Store from a remote desktop session and initiate the Windows 8.1 Update from the Windows Store, but the update hangs after the first reboot, likely waiting for the user to accept the license check. This leaves the computer unusable remotely.
Is there a way to pre-accept the license terms so that the update can complete autonomously? Perhaps an UNATTEND.XML such as would be used for an unattended clean install? Failing that, is there a way to connect with remote desktop during that phase of the install (it appears to be GUI-mode setup running with the usual Windows kernel and full OS)?