Jailbreak And Unlock iPhone 4.0: Redsn0w And UltraSn0w First Batch
Prepare yourself as the season of Jailbreaks and iPhone unlock is here, and we have the first batch of Jailbreaks as well as unlock for iPhone 4.0. The Jailbreaking tool released by Dev Team which is a developers only version has its upgrade with Redsn0w 0.9.5b2 with SMS bug fixed.
How to Jailbreak iPhone 4.0 beta.
It is just for developers and is not useful and even dangerous for your iPhone 3GS. For Mac only.
1. Download iPhone OS 4 Beta for iPhone 3G.
2. Update to this latest firmware file: iPhone1,2_4.0_8A230m_Restore.ipsw

3. Start redsn0w 0.9.5 and point it to the original iPhone OS 4 Beta firmware for iPhone 3G.
4. select “Install Cydia” and click ‘Next’.

5. Before you click “Next” make sure your device is both OFF and PLUGGED IN to the computer
6. Put your iPhone in recovery mode by pressing the Power and buttons continuously. Hold ‘Power’ button and at the same time you will now have to hold ‘Home’ button too. After few seconds release ‘Power’ button but keep holding ‘Home’ button until installation starts.

7. Once done, your iPhone 3G will restart and jailbroken with iPhone firmware version 4.0.
Your iPhone will have a blank white icon of Cydia. At this position Cydia has no sources. Go to the Sources panel and add http://apt.saurik.com/cydia-3.7 repo. Now restart your phone and you will have the regular standard Cydia logo.
How to unlock iPhone 4.0 beta
With the release of latest Fuzzyband version you can now downgrade your iPhone 3G’s bootloader. The catch here is that the bootloader on which Fuzzyband can work is 05.08 which is rare but if you are lucky to have it then it is downgradable from the iPhone 4.0 baseband 05.13.03 to 04.26.08. You need to downgrade as to unlock using ultrasn0w you are required to have it.
1. Downgrade your baseband 05.13.03 to 04.26.08. Fuzzyband Downgrader is present in Cydia, just refresh your sources and search for Fuzzyband and install the application.
2. Start ‘Cydia’ on your iPhone and tap on ‘Manage’ tab at the bottom. Now tap on ‘Sources’.
3. After tapping on the Sources option tap on ‘Edit’ and then again tap on ‘Add’. When asked to enter a url source enter http://repo666.ultrasn0w.com and tap on “Add Source”.
Cydia will now follow a series of steps to automatically update your sources.
4. Now search ‘ultrasn0w’ in Cydia and install this application.
5. Restart your iPhone.
You will now have an unlocked iPhone running on iPhone 4.0, added you have not made any mistake in following the above steps.
Meanwhile Geohot is silent and as usual we expect him to come out with a real solution to jailbreak and unlock iPhone 3GS baseband 05.13.03 and baseband 05.12.01.