3GS bootrom issue

While ALL iPhone models ( 2Gm 3G, 3GS ) can be jailbroken at any firmware versions, newer 3GS iPhones have an issue that require a re-jailbreak EVERY TIME you shut off, then restart, your iPhone ( whether deliberately or not ) ... this is called a tethered jailbreak. NOTE that your iPhone will be completely unusable until it is re-jailbroken.

This issue arose because Apple patched the exploit that hackers have been using, this impacts the iPod Touch 3 units as well.

The 3GS iPhones ( and iPods as noted above ) impacted are ones that were manufactured on or after week 40 or 2009. How to tell if your 3GS has this bootrom issue? Look at the 4th and 5th digits of your serial number to determine your production month, see Settings -> General -> About -> Serial Number. In this example, 87942 ( the first five digits of the serial number ), the third digit tells you the production year, 2009, and the 4th and 5th digits tell you the production week, 42. For this fellow, his iPhone 3GS has the new bootrom and will require a re-jailbreak after any powerdown.

I am confident that the iPhone hackers will eventually find a new bootrom vulnerability to exploit. However, I have not heard of anyone who is looking for one ( doesn't mean that no one is looking for one ).