adb backup will write an Android-specific archive:
adb backup -f myAndroidBackup.ab com.corp.appName
This archive can be converted to tar format using:
dd if=myAndroidBackup.ab bs=4K iflag=skip_bytes skip=24 | openssl zlib -d > myAndroidBackup.tar
Reference:
http://nelenkov.blogspot.ca/2012/06/unpacking-android-backups.html
Search for “Update” at that link.
Alternatively, use Android backup extractor to extract files from the Android backup (.ab
) file.