ClockworkMod

ClockworkMod, abbreviated as CWM, is a popular custom recovery for Android phones and tablets developed by Koushik Dutta (Koush) – a well-known name in the Android dev community. ClockworkMod recovery allows you to perform several advanced recovery, restoration, installation and maintenance operations on your Android device that aren’t possible with the stock recovery, and is one of the most common ways used to gain root access, back up device data, install custom ROMs, kernels, themes & mods, and more. However, for anyone new to Android customization and hacking, some of its options might prove to be a tad confusing. In what follows, we will cover all that this recovery is capable of doing, and how to do it.

Here is what we shall be covering in this guide:

1. About Android recovery
2. Introduction to ClockworkMod
3. Installing ClockworkMod
4. Booting into ClockworkMod
5. Feature tour
6. Using ClockworkMod for ROM, kernel, apps, theme or mod installation.

Now let’s take a look at each of these topics in detail.

About Android Recovery

All Android devices ship with a recovery console that is basically a partition on the device’s internal memory and can be booted into. The stock recovery of almost all Android devices provides a few basic yet handy options that allow you to factory reset your device, clear its cache partition, and recover its operating system using an official ROM in zip format, but that’s all you can do with it. That’s where a custom recovery comes handy.
A custom Android recovery basically replaces the stock recovery with one that lets you do all you can do with the stock recovery, plus a plethora of more options to give you a lot more control on your device. With a custom recovery, you can install official and unofficial ROMs as well as other updates including hacks, themes, kernels etc. using zip files, wipe not just user data but pretty much every standard partition on your device, mount the storage card for USB mass storage access without leaving recovery, partition your SD card, wipe dalvik cache and battery stats, fix permissions, perform, manage and restore backups, and so on.

Introduction to ClockworkMod

ClockworkMod recovery is one of the most widely used custom Android recoveries that is available for most mainstream Android devices. It is my custom recovery of choice here  and almost every custom ROM that I install on our devices is done using this recovery.
ClockworkMod recovery has been developed by Koushik Dutta (also known as Koush) – the same guy who brought us the Android ROM Manager. He can be found at his blog hacking away at Android devices, and at Twitter.

Installing ClockworkMod

For most devices, ClockworkMod has a dead simple installation process. This method does require you to fully root your device in order to be installed but once rooted, installing it is as simple as installing ROM Manager from Market, launching it and using its first option i.e. the one that says ‘Flash ClockworkMod recovery’.
However, in certain scenarios, the ROM Manager method wouldn’t work, or would simply not be the preferred method for your situation. In such cases, there are several other methods available to install ClockworkMod. We have covered the ROM Manager method as well as all these alternative methods in our guide on how to install a custom recovery to your Android device.
Multiple devices:

• How to install any version of ClockworkMod recovery using ROM Manager with a trick.
• Our ClockworkMod recovery coverage for guides on several other devices.

Booting into ClockworkMod

Once you have ClockworkMod recovery installed on your Android device, booting into it is quite simple. All you have to do is launch ROM Manager and tap ‘Reboot into Recovery’.
Also, if you have ADB installed on your computer, you can simply enable USB debugging mode on your device from Settings > Applications > Development, connect it to your computer via USB, launch a Command Prompt / Terminal window on your computer and enter this command:

adb reboot recovery

The above methods will not work in certain cases though, for instance if you can’t boot into Android in the first place due to some issue, or if you are using a device like the HTC HD2 that doesn’t natively support an Android recovery. Many solutions are available in these cases.

• Using hardware button combination on most Android devices:
  On most Android devices including ones by HTC, you can enter recovery by powering your device off and then powering it back on while keeping either the ‘Volume Down’ or the ‘Volume-Up’ button pressed, depending on the device. This will enter the bootloader from where you can select the ‘RECOVERY’ option by navigating to it with the Volume key and entering it with the ‘Power’ key.
  On most Samsung devices specifically Samsung Galaxy S series devices, you must keep both the ‘Volume-Up’ and ‘Home’ keys pressed while powering on the device, to directly enter recovery.
• Using MAGLDR on HTC HD2:
  Entering ClockworkMod recovery on the HTC HD2 can’t be done via ROM Manager or any hardware button combination but that doesn’t mean it is difficult in any way. All you have to do is power the device off, power it on by keeping the Power key pressed till you see the MAGLDR bootloader’s menu and finally selecting the ‘AD Recovery’ option.

Feature Tour

Now that you have ClockworkMod recovery up and running on your phone or tablet, let’s take a look at all the options it offers you to manage your Android device. We are using a Nexus S running ClockworkMod Touch recovery 6.0.2.5 but the details should apply to other devices and versions of the recovery as well.
This is what you see when you reboot your device into ClockworkMod recovery:

If you are using ClockworkMod Touch recovery, you can simply tap on these options to navigate between different sections and perform all the actions. On the non-touch versions of the recovery though, you can navigate between items using the Volume-Up and Volume-Down button, and use the ‘Power’ button to enter/launch the highlighted option on most Android devices. On devices equipped with a trackball or an optical track pad such as the G1, G2, Nexus One, HTC Desire etc., the trackball or track pad can be used for navigation and clicking it activates the selected option. Let’s review each of these options and their sub-menu options in detail now.

1. reboot system now
   This one is self-explanatory.
2. install zip from sdcard
   This option brings up the following sub-menu:
   
   
   1. choose zip from sdcard
      Lets you install any zip file from any location on your SD card. The file can be for a ROM, a kernel, an application, a theme or any mod as long as it is in recovery-flashable zip format. This is the most widely used option for installing a ROM that you have downloaded and copied to your SD card. Entering this option will bring up a screen that will allow you to browse your SD card for the zip file and select it for installation.
      
   2. apply /sdcard/update.zip
      This option can be used for installation of any official or unofficial update, ROM, kernel etc. that is in a zip format installable from recovery, as long as the file is named update.zip and it has been placed on the root of your SD card (i.e. not in any sub-folder).
   3. toggle signature verification
      This turns the signature verification on and off. When signature verification is on, you will not be able to install any custom ROMs that haven’t been digitally signed to allow installation on the device (most custom ROMs aren’t signed). Switching it off skips the signature verification check and proceeds with the installation.
3. install zip from sideload
   This option puts the phone into the new ADB sideload mode, allowing you to install zip files from your computer using the ADB sideload command introduced in Android 4.1 Jelly Bean.
4. wipe data/factory reset
   This option wipes all user data on the device as well as cache. Doing this will leave your phone in the state it was in when you bought it or when any custom ROM was first installed. It will also wipe any sd-ext partition that you might have setup (more on this later). Selecting pretty much any operation in ClockworMod (including this one) will bring up a confirmation prompt that can save you from a lot of potential trouble in case you accidentally select the wrong operation.
   
5. wipe cache partition
   Wipes the cache partition of the device to clear all the data accumulated there over use. This is often used before installing a new ROM, app, kernel or any similar mod via recovery.
6. backup and restore Undoubtedly one of the most important features provided by a custom recovery, the backup and restore feature – also known as Nandroid backup – allows you to take a snapshot of your phone’s entire internal memory including all partitions, and save it on the SD card. Here is how it looks:
   
   
   1. backup
      Takes a full backup of your device, as explained above.
   2. restore
      Lets you restore a previously taken backup. Entering this option presents you with a list of existing backups from the SD card that you can choose from for restoration.
      
   3. delete
      Lets you delete a previously taken backup to free up space on your SD card.
   4. advanced restore
      This option is similar to the Restore option but once a backup has been selected to be restored, this option allows you to choose the parts of it to restore. You can choose to restore the boot, system, data, cache and sd-ext partitions, as shown here:
      
   5. free unused backup data
      Lets you reclaim space on your SD card by freeing up any redundant backup data that isn’t required.
   6. choose default backup format
      Allows you to choose between ‘tar’ and ‘dup’ for the backup format. Leave this one as it is, unless you are sure you want to change it.
      
7. mounts and storage
   Allows you to perform maintenance tasks on all the internal and external partitions of your android device
   
   
   1. mount/unmount /system, /data, /cache, /sdcard or /sd-ext
      These options let you toggle between mounting or unmounting these respective partitions. Most users don’t need to change these options.
   2. format boot, system, data, cache, sdcard or sd-ext
      These let you directly format any of these partitions. Take extreme care with this option as formatting any of these partitions will result in losing all data on them, especially the boot and system partitions. Formatting the system partition will remove your ROM and leave your phone without an operating system while wiping the boot partition may brick your phone unless you restore or flash another one before rebooting your device. To learn more about the contents of all these partitions, see our guide to Android partitions.
   3. mount USB storage
      Lets you enable USB mass storage mode for your SD card right from recovery so that you can connect it to your computer via USB and transfer any files to/from it without having to leave recovery.
8. advanced
   This section contains a few options most users will not require, though these can come handy quite often, especially wiping Dalvik cache, which is required before most ROM installations. Here are the options from this section:
   
   
   1. reboot recovery
      Lets you directly and very conveniently reboot from recovery right back into recovery. This is useful option for certain back-to-back installations that require the device to at least boot once between them.
   2. wipe dalvik cache
      Allows you to wipe the cache for the Dalvik virtual machine (the custom-built Java virtual machine for Android).This is required before most ROM installations and at other occasions too, for fixing some problems.
   3. wipe battery stats
      Wipes the saved battery usage statistics and effectively recalibrates the battery. Useful in various scenarios when Android isn’t showing correct battery levels. This option is not shown in the above screenshot, but is present in many versions of ClockworkMod recovery.
   4. report error
      In case of errors, this feature can be used to save a log of recent ClockworkMod recovery operations on the SD card that you can later report from Android using ROM Manager.
   5. key test
      Lets you press any of the hardware keys to see if they are properly functioning, and to see their key codes.
   6. show log
      Shows you a log of your recent recovery operations.
   7. fix permissions
      Fixes the file permissions for the internal memory partitions back to default. This is very useful as a fix for several errors and Force-Closes that start appearing after you or an application you installed and provided root access end up messing up the permissions of important files.
   8. partition sdcard
      This option gives you a no-frills way to partition your SD card properly for use with ROMs that support data2ext (a very handy hack for low internal memory devices that enables an /sd-ext partition on the SD card to be used as the internal user data storage i.e. as the /data partition). Once this option is selected, you will be given options to choose the sizes for the /sd-ext partition as well as an optional /swap partition on the SD card, and will then automatically format it for you, leaving the remaining space for normal SD card usage. This option will wipe all data from your SD card so use it with caution!