How To Jailbreak IPhone 3G OS 4.0
Jailbreak IPhone 3G v 4.0
The following tutorial will outline the proper procedure in order to jailbreak an IPhone 3G with Operating System version 4.0.
Procedure for WINDOWS Operating System:
1) Download ITunes 9.2
2) Download Redsn0w 0.9.5 Beta
3) Download iOS 4.0 IPhone 3G IPSW the link at the top of the page.
Updating IPhone 3G to 4.0 - (WINDOWS)
1) Connect device to PC
2) Start ITunes and select your device from the list
3) Now hold SHIFT key and select update
4) Browse to and select the downloaded 4.0 firmware file (4.0_8A293_Restore.ipsw)
1) Once software is updated to v4.0 you may start RedSnow. Click "Browse" and select downloaded firmware (4.0_8A293_Restore.ipsw) Click Next
2) Select "Install Cydia" and any desired options and hit "Next"
3) Next you must keep your device plugged to your computer. Turn off the device. Once device has powered down hit "Next"
4) Now you must put the device into "Device Firmware Update" Mode. This is done by depressing the power button, at which point simultaneously holding the home button for approximately ten seconds.
5) Now release power but continue to hold home key until installation commences
6) Device will restart upon completion and be successfully jailbroken