Important Notes
Redsn0w 0.9.5 BETA supports only iPhone 3G (atleast for now) and requires Mac OS X. You should be a registered Apple developer or your iPhone UDID should be registered with any iPhone Dev, so you can install the beta version. If you update to OS 4.0 beta your Baseband will be at 05.13 and you will lose the carrier unlock until the next planned release of ultrasn0w and blacksn0w. Redsn0w 0.9.5 uses the same pwnage2 DFU-mode exploit that the Dev-Team has been using since the 2.x days. The current Beta of Redsn0w 0.9.5 is not meant for the average end-user.
Steps to Jailbreak iPhone OS 4.0 beta using RedSn0w 0.9.5
Step 1: Download iPhone OS 4 Beta for iPhone 3G. Step 2: Update to this latest firmware file: iPhone1,2_4.0_8A230m_Restore.ipsw Step 3: Start redsn0w 0.9.5 and point it to the original iPhone OS 4 Beta ipsw for iPhone 3G to proceed. Step 4: Now select “Install Cydia” and click “Next”. Step 5: Now make sure your device is both OFF and PLUGGED IN to the computer before you click “Next”. Step 6: Connect your device in recovery mode by pressing the Power and Home buttons continuously. Step 7: Your iPhone will reboot once it is jailbroken. I repeat. The current release will not hacktivate or unlock your phone. So if you rely on an unlock then do not upgrade to iPhone OS 4.0 as updating your firmware to 4.0 will upgrade your baseband and you will not be able to unlock it. Download Redsn0w 0.9.5 for Mac Disclaimer: This guide is for testing & educational purposes only. We are not responsible for any loss of important data or malfunctioning of your iPhone. Update 1: Apple renamed iPhone OS 4.0 to iOS 4.0. Guide to jailbreak iOS 4.0 using RedSn0w is same as this one above. Update 2: Guide to Jailbreak iOS 4.0 is here. Update 3: Jailbreak iPhone 3G on iOS 4.0 final with redsn0w 0.9.5 beta 5