When the first unibody MacBook models were released, some users noticed that one could not recognize the iPhone in DFU mode which is required for SIM-unlocking or jailbreaking an iPhone. One could not decide if this was a consequence of the specific unibody OS X version, or rather a voluntary move from Apple to slow down such iPhone-related activities. Today we know.
Indeed, the 10.5.6 update extends this incompatibility with iPhone in DFU mode to all Macs. So this is a measure to prevent iPhone owners to unlock it, at least on Mac. So, one would need a Mac running with a previous version of OS X, or using Windows, to unlock an iPhone. However, it seems that one can bypass this new "protection" by copying some Framework from previous OS X version into 10.5.6. We will try to follow and validate a full procedure.
[translation by Linathael]
