Checklist for backup and restore Android

Before migrating your data to new phone or before your phone being repaired, you've to make sure all data backed up

Back up:

1. Enable Android Auto Backup to backup apps to cloud and force backup using (on new android you can Backup to drive from Settings):
   adb shell bmgr backupnow --all
   
2. Backup apps manually using Helium by ClockworkMod (clear cache first to make backup smaller)
   If Helium is not working use this script to backup
3. Force Sync Contacts to google from Settings - Accounts
4. SMS Messages (SMS Backup and Restore by carbonite/synctech)
5. Whatsapp history (click Backup Now manually, and optionally backup to cloud)
6. Backup all files from internal storage ( copy using adb pull -a /sdcard ) 
7. Remove your external sdcard before factory reset!

Not all app can be backed up, read app documentation to backup and restore, such as Google Authenticator, Bitcoin, SMS Messages

Restoring:

1. Factory reset (remove your external sdcard first!)
2. When asked, choose install from backup or other phone
3. Connect wifi or use your mobile data
4. Continue next steps
5. Choose which app to be restored
6. Continue next steps and wait all apps restored
7. Restore internal storage ( adb push ./sdcard / )
8. Restore SMS (Install SMS Backup and Restore)
9. Reboot your phone
10. Insert external sdcard
11. Turn on phone
12. Check / setup all apps
13. Restore some app manually using Helium

Restoring using adb:

1. adb shell bmgr
   # help
2. adb shell bmgr list sets
   # list token of current and previous backups
3. adb shell bmgr restore [APP.PACKAGE]
   # restoring one package using latest backup
4. adb shell bmgr restore [TOKEN] [APP.PACKAGE]
   # restoring one application from backup set

Update 2023:

On old device: open google One, Backup, Backup Now

On new device: setup new device or factory reset first, do not scan qr or copy from old device, just add google account manually, choose "Can’t use old device" when restoring, then choose which backup to be restored

If using this method, some apps data restored, SMS restored, settings restored