So in retrospect, I freely admit that I made a bad choice when I decided to enable PCI pass through of the PCI USB controller that hosts the internal SD card reader on our PowerEdge T620. Now we are stuck in a spot where all ESXi configuration changes (related to host, not guests) do not persist and the contents of the SD card are visible only to a VM that has been assigned the PCI USB controller that is enabled for pass-through. All attempts to disable the pass through of the USB controller through the VMWare Infrastructure Client UI fail as the controller is re-enabled after the ESXi host reboots, likely because the configuration changes are unable to persist to the SD card.
So we are probably in a mode where we are going to need to boot ESXi in a "safe mode", if such a thing exists, and then find a way to change the ESXi configuration by hand through a command prompt, assuming we have the means to do so through command prompt tools.
There is an expectation that we'll be able to bring the T620 server online in the next couple of days, so any words of wisdom from those who have ideas on how to properly correct the aforementioned issue will be MOST welcome!
Unfortunately this is not a good situation.
VMware has written a knowledgebase article about this specific situation (KB2068645) - http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=206864...
For your reference: