Forum hackers netkas.org created software that allows users of Macs Pro 2009 (MacPro4,1) to update their firmware to the current EFI system of Macs Pro 2010 (MacPro5,1), allowing them to run with Intel Xeon ?Westmere? processors of six cores (hexa-core). In the 2009 generation, the maximum supported were chips quad-core.
Interestingly, the same tool can be used to downgrade firmware from a 2010 Mac Pro to the 2009 version but I don't know where that would be useful.
Although the EFI update process seems to be smooth, this hack is obviously not supported by Apple and should be done under everyone's responsibility. In addition, after the upgrade, the machine will run on 64-bit then, unless the 32-bit hardware drivers are updated (or you switch the Mac Pro's boot mode to 32-bit), those will no longer work. On the other hand, it also brings support for faster RAMs (1.333MHz) and audio output via Mini DisplayPort.
It is a way to revitalize the machines two years ago. Anyone intend to send a bullet?
(via Ars Technica)