Ok guys let me clear this upfront. I haven't tested this method yet, but by the looks of it, there is no reason why it shouldn’t work. If you have just got a new iPhone 4 or iPhone 3GS (new bootrom) which is on iOS 4.0.2, you can now downgrade to iOS 4.0.1 without having your SHSH blobs saved. This will of course allow you to jailbreak and unlock your new iPhone with JailbreakMe, and patch it with PDF Patch so that you are safe from PDF vulnerability in iOS 4.0.1.
China Unicom, which happens to be the only official and authorized carrier in the world's largest cellphone market (China) for iPhones and iPads is going to provide full service to its customers, which includes jailbreaking, converting SIM Card to Micro-SIM, installation of 10 of the most popular apps from Cydia, and a free case on every new purchase of iPhone 4 and iPad 3G. This was spotted by a Chinese citizen on a large advertising banners outside some of the China Unicom’s stores, as can be seen in the images below.
The unofficial release of PwnageTool for jailbreaking iOS 4.0.2 is now out in the wild. It can jailbreak iPhone 3GS (with old bootrom only) using iOS 4.0.2 custom firmware. There is of course no need to update to iOS 4.0.2 if you have iOS 4.0.1 (jailbroken using JailbreakMe) and PDF Patch installed from Cydia. But in case you have updated to iOS 4.0.2 accidently on your iPhone 3GS (with old bootrom), you can jailbreak it again using this version of PwnageTool for Mac.
iPhone 3GS (old bootrom only) has been jailbroken successfully on iOS 4.0.2 (custom firmware) using the upcoming Sn0wbreeze 2.0 for Windows. For those of you who don’t know, Sn0wbreeze 2.0 has been developed by the same iPhone developer / hacker which has previously released sn0wbreeze for 3.1.3, sn0wbreeze for 4.0, f0recast and BlackBreeze.
Ok guys I just tested it on an old iPhone 3G lying around and can confirm that this works! Now that Apple has released iOS 4.0.2 to patch the PDF exploit, JailbreakMe which was previously used to jailbreak iOS 4.0.1 on iPhone 4, 3GS, 3G, iPod touch 3G / 2G and iPad is now incompatible with iOS 4.0.2. But if you have iPhone 3G (which doesn’t rely on an unlock) or an iPod touch 2G (non-MC model) lying around, you can jailbreak it using the existing version of Redsn0w. Simply follow the step by step guide posted below to jailbreak the mentioned devices on iOS 4.0.2 using Redsn0w.
Apple has pushed out the new iOS 4.0.2 firmware for iPhone 4, iPhone 3GS, 3G and iPod touch 3G / 2G. This new firmware is basically a security update which patches the PDF exploit used by JailbreakMe to jailbreak all iOS devices. Now if you care about your security, you can go ahead and update now but doing so will make your iPhone 4, 3GS and iPod touch 3G / 2G unjailbreakable until a new jailbreak tool is available.