Jailbreak iPhone 4|FW=4.2.1 (8C148) & BB=03.10.01
A friend of mine was stupid enough to sell his HTC Desire and buy an Apple iPhone 4. Now he is all over me and bothering me about not being able to use a different operator/network than the one where he bought the phone. I told him numerous times about this but he didn't listen to me. So now I am supposed to help him get rid of these limitations that those bastards at Apple still keep imposing on the users of their iDevices.
So! He has an iPhone 4 with the 4.2.1 (8C148) firmware and 03.10.01 baseband!
I have been looking into this matter before, few weeks before new year. And from what I could understand it was not possible to jailbreak iPhone 4 with the 4.2.1 firmware. Only the iPhone 4 with the older firmwares 4.0.1 and possibly 4.0.2 could be jailbroken.
I found information that a new version of Redsn0w would be released on 15th of January this year. But yesterday I came across the news about the release of Redsn0w 0.9.7b7 the day earlier. The iPhone Dev Team has obviously released this new version earlier than expected - 10th January for Mac and 11th January for Windows.
Q: Is it possible to use Redsn0w 0.9.7b7 to jailbreak this iPhone 4?
Q: Is it necessary to jailbreak the iPhone before unlocking it?
Q: Is it necessary to have Cydia installed on the phone in order to install Redsn0w?
Q: How do I get Cydia into the phone if it's not jailbroken, it is not available from the App Store, is it?
Q: Do I need to use some software to extract the SHSH blob file/files before using Redsn0w?
Q: What are those IPSW files? Is that "iPhone software"? What are they used for?
Q: What other software do I need to jailbreak and unlock this iPhone?
From what I understand Redsn0w is a set of tools used on the computer to completely re-install the firmware without the limitations imposed by the manufacturer. So the "hacking" process is actually done offline on the computer itself, not on the phone directly. The hacked firmware is then transferred to the phone. Am I right?
There is actually something called tethered and untethered jailbreaking. Tethered meaning the phone has to be connected to the computer every time you need to enter a jailbroken state and the phone returns to default state when powered off or restarted. Untethered means it is independent of the computer and can stay in a jailbroken state all the time.
Correct me if I'm wrong. I am new to this, I have never done this before.
Thanks in advance!