T-Mobile iPhones unlocked post-purchase by iTunes

What's the difference between the locked Apple iPhone sold by T-Mobile Germany and the much more expensive unlocked version sold by the same carrier? Not a jot, it seems: the process of unlocking the handset is handled post-purchase by iTunes.

So claims local website MacNotesDe, which detailed the process. Buy an iPhone and pay the €600 'unlocking fee' - the unlocked version's €999 price minus the €399 T-Mobile wants for the locked model. T-Mobile records your handset's IMEI, which it then submits to Apple. Some 24 hours later, you activate your iPhone in the usual way using iTunes, but this time the handset is unlocked.

Some MacNotesDe correspondents report that the whole activation process takes place in seconds.

All of which suggests the iPhone checks with Apple what SIMs it's allowed to use, presumably by comparing its IMEI with Apple's master database of IMEIs and associated networks. Presumably the iPhone doesn't do this on a regular basis, only upon activation, so if clever hackers can figure out which bit of the handset's memory is set to enable to phone to accept or block certain SIMs, they'll have a simple way of unlocking the phones in future.

Past attempts at unlocking have involved all sorts of adjustements being made to the iPhone's radio software - aka the Baseband. Some even adjusted a handset's IMEI, which may have worked by assigned it a new number set as default to allow all SIMs by Apple's master IMEI database.

We shall see. In the meantime, the official unlocking process leaves the handset with firmware version 1.1.2. The quick activation process suggests Apple isn't re-patching unlocked handset's radio software.