Cannot restore an adb backup due to a tarball with a broken header

Question

I have two devices that have Android 5.0.2 and 6.0.1 respectively. I would like to migrate some non-cloud apps from the device with the older Android version to the new one using adb. The backing up command is simple:

adb backup -apk -f foo.bar.baz.ab foo.bar.baz

Now, after connecting the device with the newer Android version, the following command is expected to work:

adb restore foo.bar.baz.ab

Unfortunately it isn't. As usual, the restoring process fails silently just reporting that the restoring process is ended. Actually nothing really happens. Here are the logs:

adb logcat -s BackupManagerService

08-27 01:02:44.100 1300 2300 I BackupManagerService: Beginning full restore...

08-27 01:02:44.100 1300 2300 D BackupManagerService: Starting restore confirmation UI, token=1956031088

08-27 01:02:44.120 1300 2300 D BackupManagerService: Waiting for full restore completion...

08-27 01:02:45.650 1300 2450 D BackupManagerService: acknowledgeFullBackupOrRestore : token=1956031088 allow=true

08-27 01:02:45.660 1300 18181 I BackupManagerService: --- Performing full-dataset restore ---

08-27 01:02:45.680 1300 18181 I BackupManagerService: Package foo.bar.baz not installed; requiring apk in dataset

08-27 01:02:45.680 1300 18181 D BackupManagerService: APK file; installing

08-27 01:02:45.680 1300 18181 D BackupManagerService: Installing from backup: foo.bar.baz

08-27 01:02:45.690 1300 18181 E BackupManagerService: Unable to transcribe restored apk for install

08-27 01:02:45.690 1300 18181 E BackupManagerService: Parse error in header: Invalid number in header: 'Ñâ•›Ð’' for radix 8

08-27 01:02:45.710 1300 18181 W BackupManagerService: io exception on restore socket read

08-27 01:02:45.710 1300 18181 W BackupManagerService: java.io.IOException: Invalid number in header: 'Ñâ•›Ð’' for radix 8

08-27 01:02:45.710 1300 18181 W BackupManagerService: at com.android.server.backup.BackupManagerService$PerformAdbRestoreTask.extractRadix(BackupManagerService.java:7380)

08-27 01:02:45.710 1300 18181 W BackupManagerService: at com.android.server.backup.BackupManagerService$PerformAdbRestoreTask.readTarHeaders(BackupManagerService.java:7179)

08-27 01:02:45.710 1300 18181 W BackupManagerService: at com.android.server.backup.BackupManagerService$PerformAdbRestoreTask.restoreOneFile(BackupManagerService.java:6396)

08-27 01:02:45.710 1300 18181 W BackupManagerService: at com.android.server.backup.BackupManagerService$PerformAdbRestoreTask.run(BackupManagerService.java:6254)

08-27 01:02:45.710 1300 18181 W BackupManagerService: at java.lang.Thread.run(Thread.java:818)

08-27 01:02:45.710 1300 2300 I BackupManagerService: Full restore processing complete.

08-27 01:02:45.720 1300 18181 D BackupManagerService: Full restore pass complete.

It looks somewhat strange that the same backup format cannot be restored on a newer device. I've also tried to repack the underlying tarball using nelenkov/android-backup-extractor preserving the same file order (tar cvf ... -T files.lst) hoping that the broken header gets repaired. No luck.

What does cause such a backup/restore behavior and how do I resolve the issue to migrate the application from the older device to the newer one? Any help is highly appreciated and thanks in advance.

Android Debug Bridge version 1.0.31

LG Optimus E975, Android 5.0.2, CyanogenMod 12-2015...

Samsung Galaxy S5, Android 6.0.2, flashed to a newer Sprint stock firmware (initially Android 5.0.x earlier)

— Lyubomyr Shaydariv | Sources

Answer

After a whole day of various experiments with another tools like TitaniumBackup (neither worked nice, TB was only able to restore APKs, not data) I've figured out that specifying the -apk key was the problem. Simply omitting the flag during a backup operation makes it fully restorable.

So my new backup/restore plan became as follows:

device 1: backup data only

device 2: backup APK+data retaining the APK only later (requires nelenkov/android-backup-exractor by Nikolay Elenkov; can be easily built using JDK 1.8.x and Gradle 2.7 (couldn't build it using Gradle 2.7+ and Gradle 3.0+) with simple gradle command)

device 2: restore the APK using adb install

device 2: restore the data using adb restore

Here are the scripts:

backup.sh

#!/bin/bash



set -e



PACKAGE=$1



if [ -z "$PACKAGE" ]; then


 echo no package specified


 exit

fi



echo ">>> Backing up $PACKAGE data..."

adb backup -f "$PACKAGE".DATA.ab $PACKAGE



echo ">>> Backing up $PACKAGE APK..."

adb backup -apk -f "$PACKAGE".APK.ab $PACKAGE



echo ">>> Extracting APK..."

java -jar abe-all.jar unpack "$PACKAGE".APK.ab "$PACKAGE".APK.ab.tar

rm "$PACKAGE".APK.ab

APK_FILENAME=$(basename $(tar tf "$PACKAGE".APK.ab.tar | grep '^apps/'"$PACKAGE"'/a/'))

tar xvf "$PACKAGE".APK.ab.tar -C ./ "apps/$PACKAGE/a/$APK_FILENAME" --strip-components=3

mv "$APK_FILENAME" "$PACKAGE".apk

rm "$PACKAGE".APK.ab.tar



echo

echo "*************"

echo "*** Done ***"

echo "*************"

This script requires a package name as the input parameter and stores an APK and its data as foo.bar.apk and foo.bar.DATA.ab respectively. I also implemented it as a twice-backup script (a device asks for making a backup two times) because I didn't want to re-pack underlying tarballs preserving the original file order just making sure that the DATA.ab file is in its original state.

restore.sh

#!/bin/bash



set -e



PACKAGE=$1



if [ -z "$PACKAGE" ]; then


 echo no package specified


 exit

fi



echo ">>> Installing $PACKAGE APK..."

adb install -r $PACKAGE.apk



echo ">>> Restoring $PACKAGE data..."

adb restore $PACKAGE.DATA.ab



echo

echo "*************"

echo "*** Done ***"

echo "*************"

This script simply installs an APK on a target device and restores its data. The only input parameter is the application package name.

So the overall backup/restore process is:

Connect device #1

Execute backup.sh passing an application package name

Click "Backup..." on the device #1 (one will be asked two times for the data and APK+data backups respectively)

Repeat the previous two steps for other packages if necessary

Disconnect the device #1 and connect the device #2

Execute restore.sh passing an application package name

Click "Restore..." on the device #2 once asked

Repeat the previous two steps for other packages if necessary

— Lyubomyr Shaydariv | Sources

Cannot restore an adb backup due to a tarball with a broken header

backup.sh

restore.sh

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