Android backup extractor

Utility to extract and repack Android backups created with adb backup (ICS+). Largely based on BackupManagerService.java from AOSP.

Requires Java 7. Handling encrypted backups requires the JCE unlimited strength jurisdiction policy.

http://www.oracle.com/technetwork/java/javase/downloads/jce-7-download-432124.html

Usage (Eclipse):

Download the latest version of Bouncy Castle Provider jar (bcprov-jdk15on-150.jar) from here:

http://www.bouncycastle.org/latest_releases.html

Drop the latest Bouncy Castle jar in lib/, import in Eclipse and adjust build path if necessary. Use the abe script to start the utility. Syntax:

unpack:       abe unpack  <backup.ab> <backup.tar> [password]
pack:         abe pack    <backup.tar> <backup.ab> [password]
pack for 4.4: abe pack-kk <backup.tar> <backup.ab> [password]
(creates version 2 backups, compatible with Android 4.4.3)

If the filename is -, then data is read from standard input or written to standard output.

If the password is not given on the command line, then the environment variable ABE_PASSWD is tried. If you don't specify a password the backup archive won't be encrypted but only compressed.

Alternatively with Ant:

Use the bundled Ant script to create an all-in-one jar and run with: (you still need to put the Bouncy Castle jar in lib/; modify the bcprov.jar property accordingly)

java -jar abe.jar pack|unpack|pack-kk [parameters as above]

(Thanks to Jan Peter Stotz for contributing the build.xml file)

Alternatively with Gradle:

Use gradle to create an all-in-one jar: ./gradlew and then:

java -jar build/libs/abe-all.jar pack|unpack|pack-kk [parameters as above]

Notes

More details about the backup format and the tool implementation in the associated blog post.

Packing tar archives

• Android is very particular about the order of files in the tar archive. The format is described here.
• Incompatible tar archives lead to errors or even system crashes.
• Apps with the allowBackup flag set to false are not backed up nor restored.
  • (you can try restoring manually via adb push and adb shell)
• Errors are only printed to logcat, look out for BackupManagerService.

The safest way to pack a tar archive is to get the list of files from the original backup.tar file:

tar tf backup.tar | grep -F "com.package.name" > package.list

And then use that list to build the tar file. In the extracted backup directory:

tar cf restore.tar -T package.list

You can now pack restore.tar and try adb restore restore.ab