This is an FYI for something we've seen in our environment.
We upgraded a Deployment Server from SP4 to SP6 and installed the Windows 8 AIK.
When we build our WinPE4 boot images, the compression stage of the WIM build brings the server to it's knees. This causes the axengine service to lose contact with the local instance of express database, resulting in an application fault.
So..be aware that if you create your images with compression that it's worth checking that you're express service is still running afterwards.