UEFI itself shouldn't prevent dual-boot it's the 'Protected Boot', or
'Trusted Boot' section of UEFI that's the problem. Providing the
option to disable it is there then dual-boot is possible but if it has
been permanently locked there's no way to do it, even putting in a
blank HD won't allow Linux to install nor Windows as it happens - the
only thing that will load onto locked systems is the original OS as
supplied with the system. Promises a lot of fun repairing these
systems as it's likely even a Live CD or USB won't run either.

So far as I know there's no hack to get around this but then again
time will tell now UEFI is out and there will be a lot of people busy
trying to crack this one.

If it can be cracked it *will* be cracked, and the results posted for
all to see :-)