VMware Tip: Upgrade/Patch ESX 4.0 Update 1 to ESX 4.0 Update 2

It took me some time, but I finally figure it out, and it's easier than it sounds. I tried with the Update Manager, and I could not get it going in a timely fashion.

1. Power off all VMs or get them off the host, and put the host in Maintenance Mode.
2. Log in as root to the command line of the ESX 4.0 U1 host.
3. Make sure the host has Internet Access
4. Issue the following command: esxupdate --bundle https://hostupdate.vmware.com/software/VUM/OFFLINE/release-224-20100608-010422/upgrade-from-esx4.0-4.0_update02.zip --http_proxy my.proxy.home.com:443 update
5. Follow the prompts

If you don't need a proxy, simply remove the --http_proxy parameter. I think you can chnge the .zip file to be the update bundle that you want to install (i.e. Update 1, or Update 3 when it is released)

Disclaimer: I do not know the impact of this process to a "production" environment. I run this in a lab, and I have no issues if my VMs are rebooted, or are even wiped away. They were not affected, as far as I can tell.

The hint to the solution came from this article, and this document. This forum post helped too.