SLIC 2.1 downwards compatible with SLIC 2.0? Yes it is compatible! Asus Motherboard modded with DELL SLIC 2.1 Harddisk 1 installed Windows Server 2008 SP2 Enterprise with Enterprise OEM Key and DELL.XRM-MS certificate Harddisk 2 installed Windows 7 Ultimate with OEM Ultimate Key and DELL.XRM-MS certificate Both are activated! I just change the harddisk boot order in BIOS to start W2K8 server or W7.