Friday, November 27, 2009

Unlocking GSM cellphone and Manufacturer's Warranty

I often get/see questions on some of the cellphone and electronic forums that I frequent about unlocking GSM cellphones and the warranty status of doing this. Although I don't believe that this is likely, the unlocking laws in other countries might be different and what my current blog entry discusses in my experience in Canada with unlocking a phone and warranty status that I've received or didn't receive after the unlocking process.

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 or if your force the SIM and the SIM insert/attachment out of the SIM slot when removing it. 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 unless you damage the SIM slot/reader. 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. This will cause your phone to go back to its original locked state even when properly using the insert. I actually damaged the SIM slot reader on one of my phones using this method but this was probably due to my own carelessness when trying to swap my SIM card. The warranty was already expired on this cellphone and even if it wasn't expired, since the damage was caused by me and no part of "normal use", it would not have been fixed under warranty. Now, this cellphone functions as a very small Android device instead of an Android cellphone since it will no longer accept/read any SIM cards. Of course, I can still use this device to make calls using VoIP (voice over IP) using a Wi-Fi network.

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.


  1. Finally, a guy who actually understands what he is talking about. Bravo!
    Now, I will have a website to link to when people come and ask the endless "what is unlocking?" or "will unlocking void warranty?"

    Take care

  2. Thanks Erik for reading/commenting on my blog entry.

  3. Someone posted a link with a referral code for a company that he/she used for subsidy code unlocking. Although I don't have an issue with comments or recommendations or links for companies that offer subsidy key unlocking services in my blog, the links should be to the companies homepage and not using a referral link.

  4. Nice post. Easy to understand. My next question is how do you get access to the codes yourself instead of paying someone else to generate the code for you. Any software tools out there that will generate the code?

  5. Thank you "Late Night News" for reading my post and placing your comment.

    Regarding your question, about 8 years ago, I did see 2 programs that were capable of generating the unlock codes. One program was for older Nokia phones and the other program was for very old Ericsson phones. I believe that such programs do exist The programs that I saw were free on the internet.

    The newer programs that I've seen advertised on the internet were not free and I've seen online stores selling the software to generate the subsidy unlock codes based on a specific IMEI from a specific manufacturer. The software programs are generally manufacturer specific.

  6. nice information...... i got my mobile unlocked to network at here they ask me the mobile model ,country and the network name to which my mobile is locked then the imei number of my mobile finally they send me codes to unlock my mobile.

  7. Thanks sanjith for reading and commenting on my blog.

    I took a look at the site and in my opinion, it seems somewhat expensive.

    As such, people should shop around.

    Just to give some readers an idea of the prices, not including the phones that I unlocked myself (for free), I've gotten phones unlocked for as little as $5 and as high as $25 (years ago). Currently, I would not pay more than $10-$15 to unlock any phone unless I was desperate to unlock it and couldn't find or wait for any other option.

  8. Thanks dude! This just provided some much information to backed my story! My Manger and I were debating if Unlock Code would void the warranty. But looking at how it does not, you're not making any modification to the Software or Hardware. Beside, the manufacture added the feature to unlock the phone so I don't see why it should void the warranty!
    Again, Thank you!!!

    1. Thank you "Unknown" for taking the time to read and post your comment on my blog.

      There is another lock which applies specifically to iPhones which I didn't cover in this blog but the general idea is the same which is if you modify the firmware/hardware with unauthorized firmware/hardware or you damage the hardware or open the phone, the warranty is void whether these things were done for unlocking purposes or another purpose.

      The only thing you have to worry about after properly unlocking your phone using the subsidy unlock code method is that if you need warranty work done on your phone and the carrier or manufacturer can't fix the issue with your phone, they will replace your phone with either a new or factory refurbished unit. The phone that they will almost always give you will be a locked phone. This is because you originally purchased/received a locked phone.

      To unlock the phone, you will probably need to pay for a subsidy unlock code again as it is very rare that the carrier or manufacturer will unlock your new/refurbished phone for free when your original product was sold to you "locked".

      Because of this, if I purchase a locked phone from the carrier/manufacturer, I will generally unlock it (via subsidy unlock code) only after I've confirmed for the first few months of using the phone that there are no problems with the phone.