Why would you update the ISO in place for each ESXi node, you can set up a repository on a shared Datastore.
And then update the UserVars.ProductLockerLocation advanced setting on each ESXi node to point to that datastore location.
Ivo just did a post on that concept.
See Create a central VMware Tools repository
Blog: lucd.info Twitter: @LucD22 Co-author PowerCLI Reference
Thanks Luc, that sounds like it would work. We received the direction to replace ESXi ISO from an SR we submitted yesterday.
Ill go ahead and start looking to script an update to UserVars.ProductLockerLocation on each host.
Thanks Luc