iPhone 3gs are of two series one with one a fixed bootrom and another with non fixed bootrom which can be jailbreaked and unlocked. iPhone 3GS models with old BootRom [iBoot-359.3] and New BootRom [iBoot-359.3.2]. There’s a jailbreak exploit available for Old BootRom so you can jailbreak iPhone 3GS iOS 4 with old BootRom. But the New BootRom has no jailbreak exploit so the iPhone 3GS with iBoot-359.3.2 cannot be jailbroken.
So, to know whether you can jailbreak or not, you need to find out iPhone 3gs bootrom version.
- iPhone 3GS New BootRom Version is – [iBoot-359.3.2]
- iPhone 3GS Old BootRom Version is – [iBoot-359.3]
iDetector is a free to use tool which allows to find out which version of bootrom does your iPhone 3gs has, follow the procedure below find out the bootrom version of your iPhone 3gs with this tool.
1. Connect your iPhone to computer, and make sure that iTunes is running.
2. Press Home button and sleep / wake up button at the same time for 10 seconds, Then release the Sleep/Wake. Keep holding the Home button until iTunes pops up that it has found an iPhone in Recovery Mode
3. iTunes will display the message prompt when it has detected your iPhone in recovery mode
4. Now run the download iDetector tool and click the button which says Is my bootrom old or new ? you will get your answer.