First of all, for those people not familiar with what I mean by unlocking GSM cellphones, I have to explain that a lot of GSM carriers or carriers that use SIM cards (in the case with HSPA carriers) do with their cellphones. They apply what is called a subsidy lock onto the phone so that no SIM card other than SIM cards authorized by the carrier can be inserted and used in the phone. Placing another carrier's SIM card into a subsidy locked phone will generally cause the phone or device to display an "Invalid SIM:" or "Wrong SIM" message. On certain phones, you will be prompted for a subsidy unlock code.
Carriers lock the phone because generally they give a discount for the phone and they don't want consumers to use a competitor's SIM card in a phone that they've sold you. Another reason that carriers subsidy lock the phone is because when consumers travel internationally with their cellphones, they want consumers to pay roaming and long distance charges which are often quite high.
There are basically three ways to unlock most GSM cellphones. The first way involves entering the subsidy unlock code into the phone. The second way involves using customized/hacked firmware on the phone which tricks the phone into thinking that it is unlocked. The third way involves using a SIM insert/attachment in your phone. I've seen a fourth method illustrated on some websites for certain phones that would involve hardware modifications to the phone which would definitely void the manufacturer's warranty since it involves opening up the phone so I won't discuss this method of unlocking cellphones since it definitely voids the warranty.
The subsidy unlock code is a unique code that is specific for the phone (i.e. based on the IMEI number of the phone). This means that the subsidy unlock codes for one phone won't be the same for a different phone (since the IMEI numbers are different for the phones) even if the manufacturer, make, and model are the same. The method of going into the subsidy unlock code entry screen is different for the different manufacturers. Unlocking your cellphone via subsidy unlock code does not cause you to lose the warranty. I'll write more on this later in this blog entry. It is the preferred method for unlocking a phone since when the manufacturer/carrier releases an updated authorized firmware to correct specific problems to the phone or give the phone additional features, your phone will remain unlock if you apply their new firmware.
The customized/hacked firmware method to unlock your phone involves uploading customized firmware on the phone that was not approved/authorized by the manufacturer of the phone. This customized firmware tricks your phone into thinking that it is unlocked or it makes the phone not check the SIM to see if the SIM card matches the carrier. Because you are installing non-authorized software on the phone in order to trick your phone into thinking that it is unlocked, your phone warranty can be void. Another issue with this method of unlocking is that if the manufacturer/carrier releases an updated authorized firmware that fixes specific problems in the older firmware or gives additional features, if you decide to install this authorized firmware on your phone, your phone will re-lock to the original carrier.
The SIM insert/attachment method for unlocking the phone requires that you place your SIM card on top of a thin SIM-like device before inserting it into the phone. It tricks your phone into thinking that it is unlocked or that the SIM card matches the carrier for that phone. Some SIM insert/attachments require that you cut the SIM card and because you must place both the SIM and the SIM insert/attachment into the phone's SIM slot, it can possibly cause damage to the phone's SIM card reader which won't be covered under your phone's warranty. I don't see this happening unless you really have to force the SIM and the SIM insert/attachment into the phone's SIM slot. Using this method to unlock a phone also adds additional thickness to the "SIM" and depending on the phone can make removing the SIM difficult. These SIM insert/attachments have another limitation in that they don't work with all phones nor will they work with all SIM cards. The good thing about these inserts is that generally your phone's warranty is still valid. The negative thing about these inserts is that they may be rendered inactive when/if you update your phone's firmware or if you change your SIM card to a different revision of the carrier's SIM card.
Why does using the subsidy unlock method not void the warranty? The reason for this is that the manufacturer placed this into the phone (and not some hacker) and the phone's native/default firmware was written to accept the subsidy unlock code. Also, in lot of countries around the world, certain carriers will provide the subsidy unlock code if certain conditions are met. These conditions range from fulfilling the length of the contract, travelling abroad for a prolong period of time, purchasing a phone at the unsubsidized price, or just paying the carrier to unlock it. Unfortunately, currently in Canada, there is no condition that warrants the carrier giving or selling the subsidy unlock code to you or unlocking your phone. Certain carriers will unlock the phone for you at a cost but as of today, this is an exception and not a rule.
The subsidy unlock code can be purchased from various retailers/sellers that specialize in unlocking phones. The price of the subsidy unlock code varies between sellers and varies between phones but I've seen them being sold for as low as $1 and for as high as $100. Certain carriers will also "double-lock" their phones so that you will need 2 codes to enter in order to fully unlock the phone.
If you don't know the subsidy unlock code number for your particular SIM based phone, if you try to randomly enter numbers or enter a subsidy code for another IMEI, the only negative impact that can happen is that your phone will permanently lock to the carrier and you will not be able to use the IMEI subsidy code unlock method to unlock your phone in the future. The number of times that an incorrect code can be entered varies between manufacturers and phone models but once this limit is reached, your phone will be permanently locked to the carrier. This is the only "damage" that can occur if you unlock your phone via the subsidy code method.
Some customer service representatives or salespeople for Canadian carriers will say that unlocking a cellphone will void your warranty but because it is just entering a code into a phone without modifying the underlying manufacturer's software/firmware on the phone, it can't void the warranty. More importantly, another reason why it can't void the warranty is because certain carriers (in other parts of the world) will unlock the phone for the consumer under certain conditions. It would be similar to Microsoft saying that the Xbox warranty is void because you happened to push certain buttons on the gamepad/joystick in a certain sequence or a cordless phone manufacturer to say that the warranty was void because you happened to dial a specific number.
With the customized/hacked firmware approach to unlocking phones, the manufacturer as well as the carrier will often times consider that the warranty is void since the software is not authorized/official. If the original firmware can't be placed back onto the phone prior to the warranty request a lot of carriers will not process the warranty request to the manufacturer. The manufacturer will also consider that the warranty is void since the software/firmware on the phone is not the same firmware that they produced for the phone (or gave to the carrier).
If you have any questions/comments regarding this blog entry, please don't hesitate to leave a comment in the comments section.
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