Notes About the 2009->2010 Mac Pro EFI Updater (FYI to B08 Firmware users)
Just some notes on the (unofficial) 2009 MacPro (EFI/bootrom) to 2010 MacPro with support for 6-core CPUs and 1333MHz RAM. (netkas.org/?p=781). One other plus - a 2009 Mac Pro owner that updated to 2010 EFI said MDP Audio now works. (For example with ATI 5770/5870 - with 2009 EFI/bootrom MiniDisplay Port Audio was not working on 2009 Mac Pros. Officially Apple says MDP audio support requires 2010 Mac Pro.)
FYI: As mentioned in one of the later posts at forum.netkas.org/index.php/topic,852.0.html, be aware that if you have one of the 2009 Mac Pros with "B08" firmware/bootrom (MP41.0081.B08), if you 'update' to the 2010 Mac Pro EFI version and decide to revert back, it will revert to B07 firmware. (The "B08" firmware was mentioned in an article last year here on eSata cards and booting to Windows/BC volumes.)
And for anyone that updates to 2010 bootrom and is using 1333MHz ram - a later post in the thread notes zapping the pram to get ASP to report it correctly.
Also remember Mac Pro 5,1's boot to 64bit Snow Leopard by default - just a FYI in case you have some 32bit only drivers. And IIRC someone reported an issue with fan speeds/control after the update but not sure if that's common or not. (Or if SMC reset would help.)
Bottom Line - like all 'unofficial' firmware updates there's no guarantees/YMMV.
As shown in past articles here, I own(ed) a 2009 Mac Pro (Dual CPU) w/B07 firmware, but still not gotten it back from a fired part-time worker, so I've not been able to try this 'upgrade' personally. And I don't have the spare $$$$ right now to get a pair of new/faster Xeon (MP) CPUs anyway. (And for readers that missed the post/notes in July 2009, here's anandtech's article on 2009 CPU swaps that warns about _possible_ cpu/socket damage. The factory MP CPUs have no Integrated Heat Spreader, replacements do. Later pages of the netkas thread above also have notes on shimming the fan connector to ensure full seating if using IHS CPUs in Dual CPU Mac Pros.)
But single CPU Xeon upgrades are more affordable (and factory singles have IHS) - if mine was I'd be tempted to do something like this 2010 mac pro owner did - Upgrade from 2.8GHz/Quad-core to 3.2GHz 6-Core.