As we noted in today's affordable X58 motherboard round-up, manufacturers of Core i7 motherboards can submit models to Nvidia for SLI certification—but not all of them do. The folks at TweakTown have now found evidence of a surprisingly simple way to add SLI capabilities to one unsupported Gigabyte mobo.
Out of the box, the Gigabyte EX58-UD4 only supports CrossFire multi-GPU setups. However, the very similar EX58-UD4P has SLI support, and apparently, you can use a DOS flashing utility to install the UD4P BIOS on the UD4. Doing so enables SLI.
While the process might void your warranty and potentially cause your computer to catch fire, it's still surprisingly straighfroward. All you need is the UD4P BIOS file from the Gigabyte website, a DOS boot disk (a USB thumb drive will presumably do, as well), and a utility called SPIFLASH to do the actual flashing. TweakTown says the flashing process is as simple as entering "SPIFLASH EX58UD4P.F6" at the command line.