For those of you interested in customizing the vSphere Web Client login UI in the latest vSphere 6.0 Update 2 release, you may have found that after following the instructions here, the result is an empty background image. The reason this happens is that as of vSphere 6.0 Update 2, new capabilities such as a Logon Banner and 2-Factor Authentication using Smart Card support have been added. All of these capabilities are UI driven and as one would expect, they have updated HTML/CSS pages which from vSphere 6.0 or vSphere 6.0 Update 1. If you simply took the existing sample templates in my Github repo and replaced it on your system, the vSphere Web Client would not be able render them properly.
The fix is actually quite simple, instead of just copying the sample templates I have, you need to make a copy of the existing vSphere 6.0 Update 2 files (login.css & unpentry.jsp) and make the relevant code changes. Given the number questions I have received on this topic, I figure I would just create a new Github repo that contains vSphere 6.0 Update 2 specific sample themes.
Disclaimer: This is not officially supported by VMware, if you decide to enable this, please use at your own risk and ensure you backup all original files in case you need revert back to the original configurations.
For the full instructions and sample themes for customizing the vSphere Web Client login UI for vSphere 6.0 Update 2, have a look at the new Github repo here https://github.com/lamw/customize-vsphere-web-client-6.0u2 and for vSphere 6.5, have a look at the repo here https://github.com/lamw/customize-vsphere-web-client-6.5