If you own a Samsung Galaxy SII (or S2) then it’s possible your local carrier has stopped issuing Android updates. Here in NZ, most telcos (Telecom, now Spark, and Vodafone) have not offered anything beyond Jellybean (4.1.2). To check connect your Galaxy S2 to your PC using Samsung’s Kies software and see if there are any upgrades available for your phone.

UPDATE March 1, 2015: CM12 (Android 5 Lollipop) available for Galaxy S2Recently I discovered that CM12 can apparently run on the S2 which seemed pretty exciting since this is the very latest release of Android (well CM’s version anyway). Everything seemed to work fine except the Google Apps (or gapps) package didnt like my phone. Tried several alternatives but nothing seemed to fix the issues I was having so went back to an older installation.


So that’s the stock standard method of updating the operating system software (also known as firmware) on your Samsung Galaxy S2.

For some of you that won’t be good enough and you’ll want to know how you can upgrade to the latest and greatest Android system (currently KitKat – 4.4.2). To do that you’ll need to root your phone; sounds dangerous but it’s not all that bad. And if you discover the grass isn’t as green as you thought it would be then it is possible to undo and return to a stock standard firmware. I’ve actually done that recently as I was having network connection issues with the version of KitKat I was using so restored back to the original firmware I had when I purchased the phone around three years ago.

Glossary & Download Links: Samsung Galaxy S2 customising Android

It’s good to take a minute to review all the different terms related to upgrading the software on your Android phone, particularly if you’re new to customising your phone. We’re appropriate I’ve included links to a page that explains more or offers the download you need. Many of these links have been discovered after trawling the web so here’s hoping it’s a handy reference for you.

  • Original Samsung firmwareSammobile.com is a great resource with download links to original firmware for a lot of different Samsung devices including the Galaxy S2. It’s firmware chooser is also a great way to find out your CSC, PDA (Build number) and Modem (Baseband) numbers which is great for making sure you’re getting the right software for your phone (see Settings > About Device on your phone) It’s also helpful when dialling in *#1234# doesn’t work for you. This is a great website reference for situations where you want to repent of your wild customising ways and return to the original firmware – if that’s you then this tutorial explain how to do it (note it fails to mention that to get into download mode you need to hold volume down + power AND home, also you need to click Start after choosing the md5 file).
  • Samsung Kies – Love it or loathe it this is the official software to upgrade a non-rooted phone in the standard way.
  • Before proceeding with any of the hacks below make sure you are prepared to lose any apps or user data on the phone (see here to learn more about doing a factory reset, which is normally part of the custom upgrade process).

    It’s best to have the Google backup option (this will keep a record of installed apps and contacts) on your phone active as well as keeping a backup of other important app data.

    To get into Download mode on the Galaxy S2, switch off your phone then hold Volume Down + Power + Home until the Continue screen appears. For the Recovery mode (e.g. when accessing CWM) do the same except hold Volume Up + Power + Home until the welcome screen appears.

  • Rooting – Similar to jail breaking an iPhone, rooting your phone basically just involves installing a custom kernel that allows you to have superuser (root) access so you can install custom firmware. This is generally your first step when customising your phone. There are a lot of tutorials that explain how to do it: GalaxyS2Root or Mobile Networking are two of them.
  • Odin PC software – The software for your PC that makes it all possible, allowing you to install custom recovery software like CWM or TWRP. It’s also used to install custom kernels or stock firmware.
  • CWM (ClockworkMod) – A type of custom kernel, CWM is recovery software that allows you to install custom firmware such as CM11. Make sure you are using the latest version when installing KitKat.
  • Cyanogenmod (or CM) – One of the main providers of custom Android firmware. Forked (or based on) original Android software it often removes a lot of what is called bloatware (software that no one wants) and adds its own features. This is one of the 3 files you will need when upgrading your phone (the other two are gapps and a custom kernel). CM downloads are divided into different release builds with Stable being the most bug-free and Nightly the latest but potentially with more problems. If you’re not sure stick with Stable builds.
  • Gapps – If you use a custom firmware like CM (which is currently at version CM11 – the equivalent of KitKat) you’ll need the gapps software as well to be able to use all the regular Google software such as the Play store and Gmail.
  • Custom kernel – A kernel (there are several custom kernels available) is the underlying phone software (like MS-DOS is for Windows). Note that if your phone is running a custom kernel you may see a yellow triangle when you start up your phone. It’s nothing to be too concerned about and if you prefer you can remove it using the Triangle Away app or installing a stock kernel.

If you have any questions, want a new term added to the list or have a clarification just leave it in the comments section below.

Summarising the Galaxy S2 upgrade

It can all seem pretty confusing and to be honest there literally millions of articles on the web about upgrading your Galaxy S2, hopefully this helps to clarify the process a little.

Here’s a summary of the process of taking your S2 from the standard setup to a new custom rom, and back again if needed.

  1. Install Kies to make sure you can connect your phone to your PC using a USB cable
  2. Root your phone
  3. Install Odin
  4. Use Odin to install ClockworkMod (CWM)
  5. Use CWM to install CM and Gapps
  6. Optional – To return to the factory settings use Odin to install stock firmware

Let us know if we’ve missed anything!

Samsung Galaxy S2: Custom Android upgrades
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