I think you're misunderstanding me. You can use the /integrate switch to integrate the hotfix into the Windows install source. However, the hotfix will still run from svcpack.inf in order to create the needed registry entries (which tell WindowsUpdate that the hotfix is installed). When it runs, it'll overwrite the patched tcpip.sys you put in i386. So, you have two options: 1.) Copy the patched tcpip.sys AFTER the svcpack.inf stage of Windows setup. You'll need to copy it to both dllcache and system32\drivers. 2.) Put the patched TCPIP.sys in your i386 directory without using the /integrate command, so the hotfix doesn't run. If you do that, you'll need to create the registry entries that the hotfix would normally create so it doesn't appear on WindowsUpdate.