Another change you might notice in MDT 2012 Update 1 is that Lite Touch deployments never use SETUP.EXE. That doesn’t result in any real change in functionality, as we still do the equivalent steps:
So then the question becomes “why”. Well, there are a few reasons:
So does that mean you never need to import full operating system files? Not quite. They are still needed in these situations:
In MDT 2012, we used SETUP.EXE as the primary installation method, but would fall back to ImageX if SETUP.EXE wasn’t available. Now with MDT 2012 Update 1, the default is to use ImageX.
p.s. ConfigMgr 2012 SP1 will also prefer using image packages instead of install packages for the same basic reasons.