What Is Unlock (unlock, Unlock, Unlock)? [iFAQ]

Why doesn't my iPhone work with any carriers? Most of the phones Apple sells are tied to a specific mobile operator. This is Apple's business model. In the US, this is AT&T, although recently AT&T has been selling officially unlocked phones (not tied to an operator). Many mobile operators are ready to "untie" phones for a certain

fee. Under the contract with Apple, the operator is required to deduct a certain percentage of the revenue from each Apple subscriber. According to rumors, this amount is about 20%. Therefore, you can use such a phone only with the SIM-card of the operator from which you bought it. And nothing else. But, nevertheless, due to the significant difference in price between an officially unlocked phone (neverlock) and a phone locked to a specific operator, there are many ways to unlock (untie) a phone tied to an operator. Naturally, many people want to use the opportunity to use one of the most expensive phones in the world at the lowest price. And the difference in price between them on the black market, say on the iPhone 4, can reach $ 150 - 200.And in the end we have phones identical in functionality (with the exception of some nuances about which we will describe below).

Since the release of the first iPhone 2G, all models of devices (except for the recently released iPhone 4S) have been unlocked despite any protection that Apple would not put.

What is unlock (unlock, unlock, unlock, unlock)?

Unlock is a software modification of the GSM-module of the phone, which allows using the phone with a SIM-card of any operator.

There are several methods:

• Software (soft unlock) - the process takes place without interfering with the hardware of the phone, but by modifying the radio modem, which removes the check for the SIM card's membership in the operator. Typically Cydia's UltraSn0w program is used for this.

• Hardware (hard unlock) - a process by which the phone is opened and access to the modification of the software part of the radio modem is transferred using the Test Point closure.

• Sim Clone (MultiSIM) - in its essence, is not a "jailbreak". The method uses the peculiarities of verification of the SIM card belonging to the operator, with the help of which the phone is “deceived”. iPhone assumes that the SIM card belongs to the "native" operator. During use, the information necessary for authorization in the operator's GSM network (IMSI, ICCID and secret key Ki) is scanned from the subscriber's SIM card and written to a special smart card that will emulate the SIM operation. The main problem with this method is that the secret key Ki can only be read from the first generation of SIM cards (SIMv1). Requires special equipment and takes a long time.

• Sim Proxy (TurboSIM, StealthSIM, NextSIM, X-SIM and others) is a continuation of the SimClone method. Only in this case a hardware proxy is used between the phone and the SIM card. When the radio module (modem - "BaseBand") is loaded into memory, it always checks the MCC (mobile country code) and MNC (mobile network code). If the combination matches, the device is activated in the operator's network. The method is very easy to use - an adapter is applied to the SIM-card and then inserted into the phone. Doesn't require any special equipment.

Two methods are widely used now: Soft unlock and TurboSIM

Read also What is activation, hacking and how to activate iPhone ?.