Hi,
Regards update to 5.1 update 1 there is a number of methods you can employ to do this (see below):
In terms of remote access - you could:
i) enable ssh on the host and use a ssh tool (eg putty etc) to do a command-line update (using esxcli command - details included above)
ii) Can do via the actual console of your machine remotely depending on whether you have a remote management card (eg iDrac card in the case of certain Dell models, iLO in the case of HP, IBM have their own) but will need to check if you have such a facility in place
Generally i) is the most straightforward method though
Hope this helps
Many tx