Generating an iPhone secpack

A secpack is a little piece of data that is required to update the baseband on your iPhone. The file is 2048k in size and can be generated using the ICE*.{eep,fls} files that come in the Apple iPhone restore download. Once you have this file in place you can use a tool like ieraser to wipe your baseband, and then apply new baseband software using bbupdate. For a full description of what a secpack contains you might appreciate this blog post on secpack authentication.

Download one of the ipsw files from Apple. For example the 1.1.4 firmware from Apple. The ipsw file which is normally downloaded by iTunes before your phone is upgraded or restored is actually just a zip file with a different extension. Some browsers will unzip the file automatically which is sort of annoying.

You will need to visit the iPhone elite downloads section and procure 8900decrypter, and vfdecrypt (optional). These two programs will decrypt the dmg files within the ipsw zip file. 8900decrypter is the only tool necessary for getting to the ICE files. This program will decrypt any 8900 type file encrypted with the key 0x188458A6D15034DFE386F23B61D43774. iPhone elite description of 8900decrypter.