Pod2g has begun work on hacking the iPhone 4S baseband, according to tweets from the renowned hacker. Previously, pod2g had concentrated on jailbreak exploits.
As some have found, I am playing with the baseband. Already found a non exploitable DoS. I hope I can find more stuff.
His effort to hack the baseband is being performed from the network side (as opposed to the from within the iPhone) with help from a USRP N210 software radio.
Unfortunately, even if he is successful, any exploit found would need to be triggerable from the main app CPU side to be used in a software unlock.
The TippingPoint DVLabs Pwn2Own competition in September is offering $100,000 for a baseband exploit and pod2g may have his eyes set on that prize.