LiveUpdate from BE 2012 SP1 to BE 2012 SP4 failed...

Hi,

Env: BE 2012 SP1 on Win 2008 R2 - B2D2T (no de-dupe).

LiveUpdate to BE 2012 SP4 failed with 'LU1812'.

This TN:  http://www.symantec.com/business/support/index?page=content&id=TECH170556

...says that I will need the original install media - but I have two questions:

1) I don't have the original install media - so... can I use a downloaded full BE 2012 SP4 'ISO' (mounted) as the source media?

2) If I can't spoof it with a full SP4 ISO - then I'm faced with a dilemma - whilst I know that the BE instance is running BE 2012 SP1, I don't know if the original installation media was BE 2012 (base) (and then patched to SP1) or whether this instance was installed using a BE 2012 SP1 'ISO'.

What can I do?

Thanks in advance.

Dave.