What Is ClockworkMod Recovery And How To Use It On Android [Complete Guide]

ClockworkMod – also known as Clockwork and CWM – is a custom recovery for Android phones and tablets that allows you to perform several advanced recovery, restoration, installation and maintenance operations on your Android device that aren’t possible with the stock recovery. 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:

About Android recovery
Introduction to ClockworkMod
Installing ClockworkMod
Booting into ClockworkMod
Feature tour
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 and also to 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 apps, themes, kernels etc. using zip files, wipe not just user data but pretty much every 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 our custom recovery of choice here at AddictiveTips and almost every custom ROM that we 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

What sets ClockworkMod recovery apart from most other custom Android recoveries is its dead simple installation process on most devices. It 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’. We have this method covered in detail in our guide on how to install ClockworkMod recovery to your Android device.
However, in certain cases, this ROM Manager method will not work. The following scenarios will require alternative installation methods:

Your device doesn’t have an official version of ClockworkMod recovery released yet but you have found a custom version built by someone else using the ClockworkMod recovery source code.
Your device does have an official version of ClockworkMod recovery released but there is either a yet-unreleased official version or an unofficial version that you want or need to install instead.
Your device has some added protection enabled by the manufacturer preventing the automatic ROM Manager method for installing the recovery, as with some Samsung Galaxy S series devices.
Your device isn’t a native Android device but Android has been ported to run on it and it therefore requires a specialized method for installing ClockworkMod recovery, as with the HTC HD2.

We have most of these scenarios already covered and you can use the following guides to install ClockworkMod recovery if the automatic ROM Manager method fails for you.
Multiple devices:

Specific 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 recovery 3.0.0.5 but the details should apply to other devices and other 3+ versions of the recovery as well, while versions prior to 3 will have some very minor changes that shouldn’t be an issue.
This is what you see when you reboot your device into ClockworkMod recovery:
ClockworkMod Recovery 3

You can navigate these options by using the Volume-Up and Volume-Down keys to highlight an option and the ‘Power’ key to enter/launch the highlighted option on most Android devices. On devices equipped with a trackball or an optical track pad such as G1, G2, Nexus One, HTC Desire etc., the trackball or track pad can be used for navigation and clicking it can be used to enter/launch the selected option. Let’s review each of these options and their sub-menu options in detail.

reboot system now
This one is self-explanatory.
apply update from sdcard
This can be used for installation of any official or unofficial update, ROM, kernel, theme 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). Selecting this option (and most of the options featured below) will bring up a rather annoying confirmation prompt but this has saved us on multiple occasions from a lot of trouble we would have been into due to accidental key presses. This is what we are talking about:
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).
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.
install zip from sdcard
This option brings up the following sub-menu:
1. apply /sdcard/update.zip
  This one is essentially the same as the ‘apply update from sdcard’ option of the main menu.
2. choose zip from sdcard
  Lets you install any zip file (with any name) 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 as in this screenshot:
3. toggle signature verification
  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 signed by the developers (most custom ROMs aren’t signed). Switching it off skips the signature verification check and proceeds with the installation.
4. toggle script asserts
  Seldom-used option for a vast majority of users. It simply turns script asserts on or off. If you don’t know about these (we don’t), it’s best not to change this option.
5. +++++Go Back+++++
  Takes you back to the main recovery menu, obviously!
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 Nandroid backup, 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. 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 what parts of it to restore. You can choose to restore the boot, system, data, cache and sd-ext partitions, as shown here:
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.
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.
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. Partition SD Card
  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!
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.

Using ClockworkMod for ROM, kernel, apps, theme or mod installation

While in the complete feature tour we have already shown you how to install a ROM, kernel, app, theme or any similar mod from a recovery-flashable zip file using the recovery options, those of you who jumped straight to this section expecting to get just this information quickly are at the right place!
This guide is primary focused on a full feature tour of ClockworkMod recovery but in our previously written guide on how to flash a ROM or app from a zip to an Android device file from recovery, we have already covered in detail how to use ClockworkMod for installing any ROM, kernel, app, theme or mod using a recovery-flashable zip file. While that guide is based on an older version of ClockworkMod recovery, everything in it still applies to the latest versions and should work flawlessly.
That’s all there is to ClockworkMod recovery so far. We hope you enjoy using it as much as we do!

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