I have 30 days to return them for full refund. You can flash the bios to unlock the voltage. Gigabyte locked it cause the stock core is already high and people were pumping more volts in them for higher clocks then RMAing them when they burned out.
This is not true, it is HARDWARE locked. Nothing a bios flash can do.
Scyth is correct. Gigabyte chose to use a non-reference PCB with their choice of voltage controller so a bios flash may be able to raise the voltage if you change that value, but you will not have on the fly software voltage control.