There were rumors that Geohot has got an exploit to unlock iPhone 4 running on iOS 4.2.1 baseband 03.10.01 (and also on baseband 02.10.04). But the real fact is that he has no exploit to unlock iPhone 4 on baseband 03.10.01 or 2.10.04. George hotz confirmed on his blog to all his fans that Apple has closed the BB holes and he is using his iPhone 3GS instead.
From his blog:
I wish I had an iPhone unlock, the simple BB holes appear closed (my fuzzer comes up blank). In fact, I’m still using my 3GS cause I don’t have one :-/
However it doesn’t mean he can’t unlock the device. In fact he is already busy in fighting with Sony. Last month he was sued by Sony for jailbreaking PS3 devices. But that is not stopping him from finding some more security holes in the Sony product line. He has recently revealed his intention that he will be the first person to root/jailbreak Sony Ericsson Experia Play.
On the other hand, iPhone Dev Team is also working on iPhone 4 unlock and they have already made it clear that iPhone 4 unlock on baseband 03.10.01 and baseband 2.10.04 will be released after iOS 4.3 is out.
Thanks
Click On Ads To Buy iPhones Accessories
Finally, the internet was full of the news that the so called Rubysnow or whatever unlock tool will be released. All we can do now is wait for iPhone Dev team to release their tool