8Network sim unlock the Samsung Galaxy S2 i9100

I was recently giv­en a Sam­sung Galaxy S2 which was locked to T‑Mobile, and was asked if I could unlock it so that it could be used on any net­work.  I naively assumed that root­ing the phone would achieve this aim, but sadly this was not the case — it seems that some net­work pro­viders are still sim lock­ing phones, even on con­tract, and that break­ing these locks still isn’t always straight-for­ward.  With enough research how­ever, it becomes a fairly straight­for­ward process.

There are sev­er­al unlock­ing meth­ods for the Galaxy S2 which I will describe in the order I recom­mend try­ing them.  Before you start you will need to have root on your phone.  If you don’t have root I recom­mend using CF-Root or flash­ing a ROM that is already pre-rooted, e.g. Stock 4.1.2 ROM.  You will need Odin 3 to flash either root or the pre-rooted rom.  One final note of cau­tion — this guide is writ­ten with ref­er­ence to the stand­ard inter­na­tion­al Galaxy S2 which has the code GT-I9100.

1. Once you are rooted, the first and easi­er meth­od to try is to down­load Galaxy S2 SIM Unlock by Chain­fire from the Google Play store.  This is a 1‑click solu­tion which seems to have a pretty high suc­cess rate.  Unfor­tu­nately it does­n’t work on all galaxy S2’s.

2. If the Chain­fire app does­n’t work, then as per the advice in the chain­fire details, the next thing to try is an app by “Hel­roz” called Galaxy_S Unlock.  This also requires the install­a­tion of anoth­er app called Busy­box.  Install Busy­box first, run it, grant super­user per­mis­sions and then restart your phone.  Then try using the app by Helroz.

3. I found that neither of the first 2 apps was suc­cess­ful unlock­ing the par­tic­u­lar phone I had been giv­en.  For­tu­nately there are still 3 more things to try.  There is an app on the Google Play store called Galax­Sim Unlock by Spocky.  I don’t know if this is related to the work by Hel­roz (see below) or not, and I don’t know how sim­il­ar it is to the app I link below for step 4.  Look­ing at the feed­back and details though, it is well worth trying!

4. When I was unlock­ing this phone I dis­covered this app before I dis­covered the app linked in step 3.  After much read­ing and dig­ging, I even­tu­ally found what is appar­ently an older ver­sion of the Hel­roz app thanks to a thread on xda-developers which is just called Galax­Sim Unlock.  When I ran this ver­sion and restar­ted the phone, all was well!  This older ver­sion has now been removed from xda-developers as an updated ver­sion is on the Play Store.  The old ver­sion that I used is avail­able from our [int­link id=“741” type=“page”]downloads page[/intlink]

5. If none of these apps work, you can always resort to spend­ing some time manu­ally tinker­ing — the key file is called nv_data.bin which is found in the EFS folder.  You will need some kind of file explorer with root per­mis­sions — I’ve always used ES File Explorer.  To find out more about how to do this and what to look for will require quite a lot of time read­ing — mainly on xda-developers.  Use google to get you star­ted (I haven’t provided links as the avail­able advice and con­tent changes all the time)

Good luck!

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