Rooting My Samsung Galaxy S2 Android Device

By Thursday, September 13, 2012 0 , , , , Permalink 0

Finally, I have decided it’s time to root my Samsung Galaxy S2 Android device.

Some of my reasons for rooting:

  1. Installing custom ROMs / mods and kernels requires root access.
  2. Performing a good backup of the device (apps & data, system & user) requires root access.
  3. Getting rid of unwanted system apps requires root access.
  4. My M.Sc. research will include writing a kernel module for the Android kernel, so better start getting comfortable with low-level now, right?

This post is a detailed (photo-documented) walkthrough of the rooting process. The rooting is done using Odin3 and CF-Root.

Up until last year, my “mobile presence” included no more than a last-decade Nokia handset, and a Work-Issued zero-functioning Motorola i876.

During August 2011 the Nokia battery passed away (at old age, it should be noted), so I treated myself with my first Smartphone – an off-the-shelf Samsung Galaxy S II (GT-i9100) (get your own from eBay or Amazon), running Android 2.2 (I think) with stock Samsung TouchWiz.

In fear of voiding my warranty, I decided to take advantage of the first year with an Android device to explore to basic user aspects, and just be a Simple User, playing around with apps, launchers, dialers, etc.

Once the warranty reached its natural demise, I started looking at what fun stuff I can do with my device, and realized most stuff require a rooted device. Hence my first task.

The rest of this post documents the rooting procedure I performed, for self-future reference, and maybe also as a useful reference for others (who knows).

Naturally, the first thing I did was to Google for How-To guides, tutorials, etc.. As one might assume, I got tons of results. The most helpful guide I ran across was at AndroidNZ – a post titled How to Root your Samsung Galaxy S II (what a coincidence..!), which is, give or take, what I followed in order to root my own device. So here goes:

Setup & Prerequisites

  1. My PC is a Windows machine, so I pre-installed Samsung Kies, in order to have all required drivers present (looking for the “SAMSUNG Android ADB Interface” in Device Manager, as demonstrated by the screenshot)
  2. Odin3 is used to download stuff from the PC over the ADB interface to the device. I downloaded version 3.04 from, and it looked like this:
  3. Found out the current kernel version info, needed for choosing the right CF-root kernel later.
    1. On the phone, go to Settings -> About phone -> Kernel version, which looks like this on my stock Samsung ICS:
    2. Note the Kernel version string (in my case – 3.0.15-I9100UHLPE-CL200654), and write down the 3 letters that follows I9100XX (LPE in my case).
  4. Download the CF-Root kernel for the correct version from the XDA-Developers thread (simply run a search on that page for the 3-letter-version from the previous step) – I downloaded (which means CF-Root v5.5, with integrated ClockWorkMod v5.5). Extract the .tar file from the .zip file.

  5. Have the device fully-charged, and a micro-USB cable at hand.

Let the rooting commence

  1. Extract Odin3 and run it (no installation needed) – see screenshot above.
  2. In Odin3, under Files [Download], select the CF-Root-SGS2_XW_OXX_LPE-v5.5-CWM5.tar file for the PDA option.
  3. Make sure the Re-Partition option is NOT checked.
  4. Odin3 looks like this when it’s ready:
  5. Power down the phone, and put it into Download mode (simultaneously press and hold the Volume-down and Home buttons, and while holding the buttons press the power button until the phone powers up, looking like this):
  6. Confirm entering Download mode by pressing Volume-up:
  7. Now connect the phone to the PC via USB, and wait for Odin3 to recognize it (in my example – the phone was recognized on COM4 with ID 0):
  8. Press Start in Odin3 to download the kernel to the phone:
  9. Should finish pretty quickly:
  10. That’s it. The phone is rooted. This is evident both during power up, as a yellow warning triangle:
    and a little less pronounced on the About phone screen, that shows a somewhat different kernel version string:


That’s it. Hope the information comes in handy.

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