How to update ESXi 5.x to the latest build of 6
Sign into VMware and start the trial for VMware vSphere:
https://my.vmware.com/group/vmware/evalcenter?p=vsphere6
Use VMware Software Manager to download VMware-ESXi-6.0.0-2494585-depot.zip
http://www.vmware.com/products/software-manager/
Using vSphere Client upload to local datastore, enable SSH, enter maintenance mode and run the following command:
esxcli software profile update -d /vmfs/volumes/datastore1/updates/VMware-ESXi-6.0.0-2494585-depot.zip -p ESXi-6.0.0-2494585-standard
Reboot and verify version 6.0.0, 2494585
vmware -vl
Download and apply latest patches:
https://www.vmware.com/patchmgr/findPatch.portal
esxcli software vib update -d /vmfs/volumes/datastore1/updates/ESXi600-201504001.zip
Reboot and verify version 6.0.0, 2615704
Reference:
http://www.vladan.fr/easily-upgrade-esxi-5-x-to-the-latest-esxi-5-5-update-1-via-cli/
http://www.v-front.de/2015/03/vsphere-6-is-ga-ultimate-guide-to.html