The latest 5.1 3gs jailbreak available is RedSn0w 0.9.10b8b that was released on 5-May-2012 by iPhone Dev Team. This latest jailbreak for iOS 5.1 is tethered for all other devices except iPhone 3GS, yes it is untethered for 3GS if it is running the old bootrom. This is a good luck for 3GS users that they can jailbreak their devices untethered on any firmware version if their device has the old bootrom.
Many of you may not know whether your 3gs has old bootrom or new bootrom. I am giving below stepwise procedure to know if your iPhone 3GS has old bootrom or new. If you find that your 3gs is on old bootrom then Congratulations. You can just follow this How to jailbreak iPhone 3gs 5.1 Untethered tutorial and enjoy the benefits of jailbreak app called Cydia and many other jailbreak tweaks.
So here is how to find your iPhone 3gs bootrom version:
1. Put your 3gs in DFU (direct firmware update) mode. To enter DFU mode turn your iphone 3gs off and:
- Hold both Power and Home buttons for about 3 seconds (till as soon as Apple logo appears)
- Now release the Power button but continue holding the Home button for 10 more seconds (screen will go blank) and now your device should be in DFU mode
2. On your computer: Open the Control Panel and then open Device Manager. Scroll down the device list to find “Universal Serial Bus Controllers” expand it and find Apple Mobile Device USB Driver. Right Click and click Properties a new properties window will appear click Details. In the Property list click the list arrow and find and click “Device Instance Path” You will find a windows like in next steps.
3. Check the value displayed as in the below window:
If the value at the right most side is something like [iBoot-359.3] congratulations you have old bootrom.
And if this is [iBoot-359.3.2] then it is new bootrom and your device can not be jailbroken at iOS 5.1 untethered with the current version of RedSn0w and you have to wait if you want only untethered 3gs 5.1 jailbreak.
In both cases you still can jailbreak iphone 3gs on 5.1 but it will be tethered for new bootrom. So if you have decided to jailbreak your 3gs just follow this Jailbreak guide for 5.1 3gs jailbreak.
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