Before upgrading your iPhone to iOS 5.1 you must check that your iPhone has old bootrom because if your iPhone has a new bootrom then each time your reboot you must connect it to computer. You must save your SHSH blobs before continuing to upgrade.
Create a new folder Pwnage in which you will copy these files.
- Redsn0w (Tool used for Jailbreak and unlock)
- 5.1 (iPhone 3GS): 5.1: iPhone2,1_5.1_9B176_Restore.ipsw
Launch iTunes after connecting you iPhone to a computer.
Now just select your iPhone from the list of devices from the left sidebar. Here we will install the Custom Firmware for doing that hold down SHIFT key and click RESTORE Button.
Select firmware IPSW file from Pwnage folder. Click then OPEN Button to continue for restoring iPhone.
After restoration is completed to the desired firmware then now its time to launch redsn0w.exe but right click it and Run as Administrator so that we will Jailbreak and unlock iPhone.
After Redsn0w opens now next step will is to click JAILBREAK button.
Switch OFF your iPhone and then click NEXT button.
Now you must enter into DFU mode and Redsn0w will guide to through.
Now hold HOME and POWER button at same time for 10 sec.
Now release POWER button but hold HOME button until device is detected by Redsno0w
iPhone will now reboot
New kernel will now uploaded, it may take couple of minutes.
Now select the Install Cydia and Click NEXT
iPhone will reboot and then upload RAM disk and Kernal.
Once Redsn0w processes will be completed iPhone will reboot it may take 5 minutes.
This tutorial is for educational purposes only; iphone4maintinance will not be responsible for any loss of data or damage of iPhone.