I have the above ESXi Server running. My intention is to somehow upgrade to U3 or better U4 remotely without entering the server room and performing a fresh install. But the vSphere Host Update Utility 4.0 does not find patches for this host and I cannot find upgrade packages for U3 or U4 for manual download, only ISOs.
I have no vCenter. This is only a stand alone ESXi Server.
Have you tried the VMware Infrastructure Update Utility instead of the vSphere Client Update Utility? I wonder if it isn't finding updates because of that.