Changing the Display Resolution in Windows PE during LTI
You can specify a different display resolution using the unattend.xml contained in a Lite Touch Windows PE boot image. In MDT 2010, the XML template files for boot images are Unattend_PE_.xml where is either x86 or x64. These template files are found at C:\Program Files\Microsoft Deployment Toolkit\Templates\. By default, these template look like this:
Lite Touch PE
To change the display resolution for Windows PE, modify the appropriate settings shown above. Note however that by default Windows PE uses the Standard VGA driver, so this will limit your available resolution choices unless you inject additional out-of-box video drivers.