Thank you, Ryan (and +1, of course)! Did I read correctly that this does a full backup including all data? So there's no snag (except one needs the SDK installed)? Almost sounds too good to be true! And also thanks for your shameless self promotion xD

BTW: Adding to your solution, just today I found a post on the XDA News: Ultimate Backup Tool, No Root Required. This "Ultimate Backup Tool" is just a simple .bat file calling the ADB commands you mentioned (Pastebin) -- and thus can serve as "inspiration" to Linux/Unix/Mac friends to create a similar shell script ;)

Yes, it does data. Actually, it does the data only by default. The only snag is that it is for 4.x devices and it is a pretty much undocumented feature of adb.

Does this include contacts, messages, applications, settings, bookmarks ?

This can back up everything, it can even include all of your sdcard data if you want.

Does this only work for same device restore, or same model? I have to get my phone replaced (One X with dodgy wifi) and would like to be able to restore everything to the new version...

@cjk As long as it is the same version of android and the same phone model you should have no problems.

I tried this (should say I'm in the process of trying it). Be aware that the backup is quite slow. It seems to run at about 1Mbyte per second, so plan a few hours tethered for a phone with a lot of data. Also, be aware that the ADB command has a timeout. If you issue the command, you have about 20 seconds to enter the password and hit "back up my data". Otherwise ADB drops back to the command line.

Has anyone verified that this type of backup will work for rooting? Specifically, if I back up, root the phone (which wipes it), and then restore the backup, will the phone still be rooted? Or will it revert to the state it was in when I created the backup?

If I backup with this method first then root it, increase flashing counter and then restore with this method, will my phone get back to "100% original stock" one ?

! Beware ! adb restore is far from complete, at least on an unrooted stock Android 4.3 on a Nexus 3! A few things are restored, a few not! I checked restoration of some features. NOT RESTORED, basically all the key telephony features: Contacts, sms, ringtone&notification sound, activated input languages (=kbd layouts), ownername (ownername set in first boot wizard is kept instead) PROPERLY RESTORED: Custom vocabulary, wallpaper, launcher icon positions, apps and their settings. Closing statement: This is an unsuited backup solution! Would adb backup complete on rooted phone?

I read & considered: pof.eslack.org/2012/07/30/… and android.stackexchange.com/questions/36830/… thus the idea of an unrooted full backup was promising, but sadly after testing myself not factual. So for a full backup it seems, one has to use a custom ROM. Hopefully one, which flashes the /recovery/ only temporarily, when it needs to update /system/, and locks the bootloader again thereafter.

@RyanConrad is this method only to backup the apps or it will make the copy of the rom also? So if anything goes wrong with the phone like bootloop, will I be able to restore the phone to original state?

@sameer I dont think this will help in a boot loop situation. The backup and restore require you to be in the android OS to run them.

I think this is a terrible answer to the question - if your device is unrooted it will appear as if correct backup is being created, but you will only discover the truth once you try to restore it. Please emphasize the -nosystem option.

From the xda-news link: " It’s worth mentioning that this is not like a nandroid backup which is effectively a snapshot of your current device set up, this backs up apps, app data and information stored on the internal/external SD card."

I have set up multiple users on my Nexus 7-2013 tablet. Will this backup/restore app/data for all users or just the first (primary) user?

@RyanConrad I guess this answer might require some updates: apps can opt-out of adb_backup (setting ALLOW_BACKUP to "no" in their Manifest files). If "root users" want to work around this, there's the Backup All Apps Xposed module, but no way around it without root. Maybe you also should point out what is not covered (apart from what you've already mentioned – see porg's "!Beware!" comment above). Plus maybe integrate other hints from the comments, and then request a comment cleanup?

Another reason this answer is unsatisfactory: the rationale for backup/restore is due to hardware failure of obsolescence.... this requires the ability to restore on a different device, but apparently adb backup is completely unsuited for the task: android.stackexchange.com/questions/37570/…

Ryan, that 4.0+ reads (it could be my incorrect interpretation) like the solution is applicable only to Android versions 4.0.*-4.4.*. Can you make it more explicit to show that it works for Lollipop and possibly, Marshmallow as well? Thanks! I fear it might change the intent so I didn't edit myself.

Well, SMS is app data of the Messaging application or so, so it should be backed up unless the app disallows that. In my experience, SMS data are backed up. Some vendor-customized phone might however exclude it.

⚠️ Be aware that an app can explicitly prevent backing up its data by setting android:allowBackup="false" in its AndroidManifest.xml. See developer.android.com/guide/topics/manifest/…. Running adb backup... will not save any data for these apps. Example apps that forbid backups are WhatsApp, LineMessenger.