Bootrom

Introduction / old+new

Please see also Apple's stage 2 bootloader, which also uses the "iBoot" name.

Often users refer to old bootrom or new bootrom devices. The new bootrom devices were released after 9 September 2009 and have the 0x24000 Segment Overflow fixed. Therefore these newer versions of the iPod touch 2G and iPhone 3GS are not vulnerable to this exploit and had only a tethered jailbreak/unlock until Spirit came out. Currently, these devices can be jailbroken on iOS 4.0 with Star.

Check bootrom version

To find out if you have an old or new bootrom, the easiest way is to look at the serial number. If the 4th and 5th digits are lower than 40, then you probably have an old bootrom. If they are higher than 45, then you probably have a new bootrom. These two digits show the production week. For refurbished phones and for numbers inbetween, the result is undefined and you have to make the following exact check.

The exact check to find out which bootrom you have is to put your iPhone 3GS into DFU mode. Double-check your phone is in DFU mode and not in Recovery mode. If you have Mac OS X, go to System Profiler, and under the "Hardware" category, go to USB, and click on "Apple Mobile Device (DFU Mode)." If you have Windows, go to Device Manager, find USB controller, subitem Apple Mobile Device USB Driver. In Properties, Details, select Device Instance Path in the dropdown. The end of the info string will show the bootrom version.