However in my case I was unable to install the x86_64 version.
For some reason my CPU gets identified as i686 in the 'Home' tab. By checking this manually (uname -m) I also get the same result. the processormodel itself was correctly identified as 'i5 4460T' using 'cat /proc/cpuinfo'.
This is strange as the Intel i5-4460T processor is of course 64 bit. And if I check the processor on the same machine (and same BIOS settings), but now using Xubuntu as OS, I get x86_64.
Can it be that this is caused by the fact that Snakeoil is 32bit and thus the processor is already running in 32 bit mode?
Unfortunatly I couldn't revert back to an earlier version of the firmware as I got an error message.