Nexus S (GSM) ClockworkMod (CWM) Recovery AIO Guide

ClockworkMod recovery (abbreviated as CWM) is the most popular custom recovery for Android devices, developed by Koushik “Koush” Dutta. CWM recovery replaces the stock recovery that is present on every Android device and extends its functionality with a lot more features and options.

The one thing that CWM is mostly used for is flashing custom ROMs on devices, which are basically custom versions of Android that replace the default software that a manufacturer puts on their devices. Other functions of CWM include the ability to factory reset a device, backup and restore a device’s ROM, and flash custom kernels, hacks, and mods.

In short, CWM recovery is a powerful tool that has made a whole world of custom development and mods possible on Android, since the early days when the first Android-powered smartphone was released, and is available for almost any Android device out there.

This all-in-one guide puts together everything that one would need to flash CWM recovery on their Nexus S, along with step-by-step instructions of the entire procedure, so that you can start flashing custom ROMs and make other modifications on your device.

Installing CWM recovery will void the phone’s warranty, and as install a custom recovery requires unlocking the bootloader on the phone, it will also wipe all the data on the phone and factory reset. However, by flashing a stock firmware image and recovery and re-locking the bootloader, warranty can be regained, and you’ll be able to back up and restore all data before and after flashing CWM recovery.

Now let’s get started with the methods to install CWM recovery on the Nexus S. Remember, you need to use any one method, with the first one being the easiest and most straightforward.


The procedure described below is only for the GSM variant of the Samsung Nexus S. Do not try it on the CDMA/4G Nexus S variants or any other device.


The methods and procedures discussed here are considered risky, so try them out at your own risk, and make sure to read each step carefully before attempting anything. We will not be held responsible if anything goes wrong.

Things you need:

  1. Take a backup of all the data on your phone. Flashing CWM recovery requires unlocking the bootloader on the phone which wipes everything from the phone and factory resets it. Use our Android Backup Guide for help on how to back up apps and other data, such as contacts, SMS, bookmarks, etc. Then, after you’ve backed personal data up, copy everything off the phone’s storage to a computer.
    • NOTE: Backup is optional and you can skip this step if you do not wish to back up anything.
  2. Unlock the bootloader on your Nexus S using this guide. Unlocking bootloader wipes all data from the phone so make sure you take a backup as mentioned in step 1.
    • NOTE: If you’ve already unlocked the bootloader on your device, you can skip this step.
  3. Download and install the Android SDK → from here. This will install the necessary drivers for the phone on your computer.
    • NOTE: If you’ve already installed the SDK when unlocking the bootloader, skip this step.
  4. On the phone, go into the Settings » Developer options menu and enable the USB Debugging option. On Android 2.3, this option can be found in Settings » Applications » Developer options.

Method I: One-Click Root Toolkit

The One-Click Root Toolkit is an automated toolkit that installs CWM recovery on the phone with little input from the user. This is the most straightforward and simple method, specially for those not interested in typing in all the commands needed to flash recovery themselves.

NOTE: The toolkit will also root the phone along with flashing CWM recovery.

  1. Download the toolkit from the source page.
  2. Extract the downloaded toolkit file to obtain a folder named “sabra-root-toolkit”.
  3. Start the Toolkit by double-clicking on the “root” file inside the “sabra-root-toolkit” folder. A few animations will play after which you’ll be asked to press any key to continue. Do so, and keep pressing any key to continue until the toolkit asks you to connect the phone to the computer.
  4. Connect the phone to the computer, then wait for the drivers to finish installing. Note that driver installation will only take the first time you connect the phone after installing the drivers. Then, press any key on the keyboard to continue.
  5. To use/select an option in the toolkit, we need to enter the number corresponding to an option and then press Enter to select that option. For example, if the Nexus S is listed as “3- Nexus S“, then we need to type in 3 in the toolkit window, then press Enter. Keep this in mind as we go to further steps.
  6. Now, do the following in the toolkit once you get to the device selection screen:
    1. Select the “Nexus S” when asked to select your device.
    2. Then, select “Unlocked” as we have already unlocked the bootloader.
    3. When asked to choose between installing “super user” or “SuperSU”, select “SuperSU”.
  7. Once you select “SuperSU”, the rooting procedure will start. Your phone will restart, ClockworkMod recovery will be installed, then the root files will be installed, then when the procedure is complete, the phone will reboot back into Android.
  8. ClockworkMod recovery is now installed on your Nexus S. Make sure to read the “Booting into ClockworkMod Recovery” section after method II below to find out you can boot into CWM when needed.

Method II: Using Fastboot

The fastboot method involves using the command prompt on the computer and performing all the steps manually for flashing CWM recovery. This method has the advantage that you’ll be able to learn of the actual commands that are used, as opposed to the toolkit which performs the actual flashing process automatically.

NOTE: The fastboot method will NOT root the phone.

  1. Download Fastboot files, which will be used for flashing the recovery.
    Download Fastboot | Filename:
  2. Extract the file on your computer to the C: drive to get a folder named Fastboot with four files inside it.
  3. Download the touch version of ClockworkMod recovery from the official ClockworkMod downloads page, for the “Nexus S”. Remember to download the file from the last column on the downloads page under the “Touch” section, which is the touch version that we need to download. The file should be named something like “recovery-clockwork-touch-*.*.*-crespo.img”, where *.*.* will be the version of recovery.
  4. Copy the CWM file that you downloaded to the Fastboot folder on drive C so that you now have a total of 5 files inside.
  5. Turn off your phone. Then, boot into fastboot mode by holding down the Volume Up + Power buttons together till Fastboot Mode shows up on screen.
  6. Then, connect your phone to the computer with your USB cable, then wait for Windows to finish installing the drivers (drivers will be installed only the first time you connect the phone to the computer). For reliability, ensure that you use a USB port at the back if you are using a desktop computer, as the front panel ports can be loose and cause problems.
  7. Click on Start menu » All Programs » Accessories » right-click on Command Prompt and click on Run as administrator. If you are using Windows 8, this can be done by right-clicking on the extreme bottom left corner of the taskbar, then selecting “Command Prompt (admin)”.
  8. Now, perform the following steps in the command prompt to flash CWM.
    1. Navigate to the Fastboot folder which you obtained in step 2. For example, if the Fastboot folder is in drive C on your computer, enter cd C:Fastboot in command prompt (and press Enter) to navigate to the folder.
    2. Then, enter fastboot devices. If your Nexus S has been detected properly, you will see a device ID show up in command prompt. If nothing comes up, make sure you have installed the drivers, disconnect phone, remove and re-insert battery, and retry the procedure from step 5.
    3. Now, flash CWM recovery on the phone by entering fastboot flash recovery *filename*.img in the command prompt, where *filename* has to be replaced by the name of the recovery file that you have downloaded. For example: fastboot flash recovery recovery-clockwork-touch-
    4. After recovery is flashed, you will see an “OKAY”/”finished” message in the command prompt. The phone will also show “FASTBOOT STATUS – OKAY” at the bottom of the screen once recovery has been flashed.
    5. Now, using the volume buttons on the phone, press the volume down key to highlight “RECOVERY”, then press the power button to boot into recovery. Once recovery boots up, simply select the “reboot system now” option to reboot the phone into Android.
  9. ClockworkMod recovery is now installed on your Nexus S. Make sure to read the “Booting into ClockworkMod Recovery” section below to find out you can boot into CWM when needed.

Booting into ClockworkMod Recovery

Whenever you want to use CWM recovery, you can boot into it via Fastboot mode. The procedure to boot into CWM recovery is given below.

  1. Turn off the phone.
  2. Then, boot into fastboot mode by holding down the Volume Up + Power buttons together till Fastboot Mode shows up on screen.
  3. Press the volume down key till the “RECOVERY” text is highlighted in fastboot mode, then select it by pressing the power button. The phone will then reboot into CWM recovery, where you can tap on options to select them.
  4. Rebooting back into Android from CWM recovery can be done by selecting the “reboot system now” option in the main menu of CWM.

ClockworkMod recovery is now installed on your Nexus S, and you will be able to flash custom ROMs, hacks, kernels, take backups of and restore ROMs, and make other modifications such as factory resetting the device. If you run into any problems, let us know in the comments and we’ll help you out.