Updating Hosts
When you add custom drivers or patches to a host, the process is called an update.
Update ESXi 4.0 and ESXi 4.1 hosts with the vihostupdate command, as discussed in the vSphere Command-Line Interface Installation and Reference Guide included in the vSphere 4.1 documentation set.
Update ESXi 5.0 hosts with esxcli software vib commands discussed in the vSphere Upgrade documentation included in the vSphere 5.0 documentation set. You cannot run the vihostupdate command against an ESXi 5.0 host.