Hi Macrumors, I'm not sure if it's just me but i've found a bug in FW 3.1.3. I have an official unlock iphone 3G(NZ). After 3.1.3, i got native tethering working(non-jailbreak). But when i connect USB tether my iphone to my mac, it drains the battery of the iphone when it's suppose to charge. Then i tried with bluetooth and keep the iphone plugged in to charge while i'm tethering via bluetooth. It still drains the iphone battery. I don't understand how can the battery charge drains when the iphone is being charged. Has anyone experienced that as well. So it means no matter what your iphone battery will discharge when tethering. Sounds like a bug to me!