There is no official jailbreak utility for iOS 4.0.1. However you can still jailbreak and unlock iPhone 3G. Just do the following:
Here’s what hackers tweeted about new Apple firmwares 4.0.1 for iPhones and 3.1.2 for iPad:
As with *any* new FW, jailbreakers + unlockers must avoid this upcoming 4.1 update until our tools are updated
3GS, ipt3G, iPhone4 users (regardless of current FW or JB status) should backup 4..0 SHSH blobs http://is.gd/dskh9 soon
Obviously avoid today’s 4.0.1 update until JB tools are updated. Luckily, no baseband change so ultrasn0w lives on
each FW version has unique blobs. But using http://is.gd/dskh9 you can get 4.0 blobs on PC while you stay at 3.1.2
Hah for those iPhone3G or ipt2g(non-MC) users at 4.1beta1: use redsn0w from 2 wks ago to JB http://is.gd/dstU3
by the way, there is absolutely no reason to update to 4.0.1. it only improves the formula for _displaying bars_, not actual signal
There’s no baseband update, so signal strength or radio performance cannot have improved.
Hey guys, I recommend any iPhone 4 users who need jailbreak or unlock use http://3.ly/zN58 to back up their SHSHs NOW, and not upgrade.
WARNING: 3.2.1 for the iPad is out. It KiLLS the Spirit Exploit. 4.0.1 is out too (not for the iPad though)
Congratulations to all iPhone users. iPhone 4 has been successfully jailbroken. iPhone hackers @planetbeing and @chpwn has managed to get root access on the device using @comex’s userland jailbreak method. However do not expect new jailbreak utility soon. @p0sixninja has confirmed that it cant be released in its current shape because it contains some of Apple’s proprietary code:
@i_Enthusiast the jailbreak shown is a more of a stepping stone for us, it can’t be released because it includes some of apples software
You should not expect the carrier unlock soon too. This is because iPhone 4 uses a new baseband OS, which will require a complete rewrite for ultrasn0w unlocking tool:
The DevTeam and others have been checking through the iPhone 4, and have noticed the baseband runs a completely different OS than on previous models. The iPhone 3G and 3G[S] both ran Nucleus OS on the PMB8878 baseband CPU (aka XGold 608), where the iPhone 2G ran the PMB8876 (aka S-Gold 2). iPhone 4 uses the PMB9800, or X-Gold 618 – running a separate OS – ThreadX, an RTOS by ExpressLogic.
Fuzzyband is an application that can downgrade the baseband for iPhone 3G. Recently it has been updated to include the support for firmware 3.1.3 baseband 05.12.01. It works only with bootloader 05.08 (early iPhone 3G).
Why do users need to downgrade the baseband? The answer is simple: if they accidentally upgraded the new firmware and need to run unlock software (blacksn0w and ultrasn0w). Unlocked iPhones do not need Fuzzyband. iPhone 3GS users cannot downgrade baseband with Fuzzyband.
Fuzzyband is available for jailbreaked iPhones in Cydia (repository BigBoss, category “System” ).