The HTC G2, which's perhaps one of the most anticipated phones in recent months, has a new mechanism that prevents the loading of custom software. "Some excited rooters at XDA Dev Forum tried to root the G2 -- namely to unlock the software so they can add their own programs and control to OS -- and ended with a built-in lock in the G2 hardware that returns the handset to the stock state upon rooting. That's right: it's a self-repairing system, like grey goo."
As per Gizmodo, there's a special microchip in the phone that'll override any changes made to phone and re-install original firmware. Developers over at XDA are still busy scratching their heads over this one. Some are even calling to Lords of Modders (aka Cyanogen and Team Douche) for help.
Chris Soyars' notes that Team Douche is still in the stages of figuring out how the lockdown actually works. One may wonder how a carrier could send an over-the-air update if the phone will just flash itself back to its original firmware. This thought process is precisely why the community believes there to be a way around the problem. Soyars even says, "If the carrier can give us an update, we can give you an update. It's that simple."
More Info: XDA Forum