my best advice with a bios is 'if it works leave it', what sort of "tweaking" do you wish to do? unless it's for overclocking i cannot think of the top of my head what else you want to do, i have seen/heard of many a good mobo going to the great scrap heap in the sky due to bios updates that have gone wrong. Again, my best advice leave it alone!!
Of course others will completly contradict me but that's the fun of the forum!!!!