Updating PVS Images using XenServer Direct Boot and NFS

As discussed here are the two references to setup an NFS share to enable you to direct boot a PVS vDisk on XenServer without having to Reverse Image: -

http://forums.citrix.com/thread.jspa?threadID=255144&tstart=0

http://support.citrix.com/article/CTX123395

This procedure worked perfectly for me when I had to update the PVS tools from version 5.1 to version 5.6