See the last post was December 17th, 2012 and still no solution from Gigabyte.
Here's my 'report':
The problem also appeared on my GA-Z77-DS3H v1.0 F9 using a Dynex FW800/400 PCIe card with an
LSI L-FW643E-6 8P Chipset. This card worked flawlessly on a P35-DS3L/Q9550 rig under 10.4 - 10.6.8!
I tried pulling everything out until I narrowed it down to the FW card. I even did a fresh install on a spare HD with nothing added or modified. NO JOY; with FW card in place, Sleep & Shutdown just won't work properly.
Put everything back to original minus the FW and Sleep/Wake now work correctly.
I just updated to UEFI on my GA-Z68X-UD3H-B3 and had the same boot loop problem with the StarTech Firewire card. Everything else is so much better with UEFI that it didn't bother me too much. But under the old BIOS I was overclocking my CPU. Now with UEFI if I made any changes to the CPU multipliers, I'd just get a blank screen. I had found this thread while troubleshooting my boot loop problems and on a hunch I pulled out the StarTech card then increased my turbo CPU multipliers and suddenly everything worked perfectly. I don't hold out any hope for a fix on my old motherboard, so I just ordered a Syba card.
Got a Syba SD-PEX30009 PCI-e 1394B/1394A card from Amazon Warehouse Deals ($18).
Installed tonight and everything tested OK. Sleep and Wake now working perfectly
and I've got FW800 again, yipeeee
After installing the StarTech Firewire PCIe card, I was able to solve the Shutdown/Restart issue on Gigabyte boards where the option "PME Event Wake Up" (Power Management Settings) is present.
As you already pointed out in your article dated August 7th, 2012, disabling the PME option solves many unwanted Restart issues. On a GA-H67MA-USB3-B3 board the issue is solved, but on a UEFI based GA-Q77M-D2H the option is missing and I don't know what to do next...