I've just installed Service Pack 1 on a Windows 2008 R2 server that is hosted in a remote datacentre with no possibility of logging in with a 'real' screen and keyboard. SP1 seems to have broken Remote Desktop protocol (RDP), I get to the log-in screen, log in and briefly see the Welcome message, then the RDP session is terminated like so:

The original release of the update from KB2667402 causes this issue. It notes in the known issues that applying SP1 after the update causes RDP issues.

The patch was re-released to address and correct the RDP issue.

So, you should be able to start the server up normally and remotely uninstall the original version of the patch via WMI

wmic /node:<SERVER> /user:<USER> process call create "powershell wusa /uninstall /kb:2667402 /quiet /forcerestart"

After uninstalling the KB and the subsequent forced restart, you should be able to RDP to the server again. At that point, you should be able to install the updated version of the same KB

Footnote: This did solve the problem but it wasn't necessary for me to use WMI remotely. I was able to boot into safe mode using the virtual KVM and use the WUSA command line directly to uninstall KB2667402. All was then working after a reboot. This allowed me to sidestep all the firewall and permissions issues associated with letting a remote user access WMI.