Migrate data from device to device

kwah

As a user, which has got a new UBports device, I would like to migrate all data from my currently used UBports device to the new one.

What can I do? Is there "simple" backup / restore howto addressing the user story above?

Quick search in interwebs and this forum returned a big number of discussed topics mainly on synchronizing various data categories to / from PC, but I could not find any consistent story about migration from device to device. If you know one - please comment.

guru

I have not done this (and perhaps would not do that), because IMHO it's better to move certain app data selectively. How to move, for example contacts, is written "in stone" here: https://gurucubano.gitbooks.io/bq-aquaris-e-4-5-ubuntu-phone/content/en/chapter9.html

Flohack

A complete backup should work as follows:

Connect your device with USB and have adb ready
Issue adb reboot recovery
Create a local directory for the backup and cd into it
Issue adb pull /data/system-data and adb pull /data/user-data
This will take a while each. If everything goes well you should have both folders in your backup directory

A restore is the other way round:

Connect your device with USB and have adb ready
Issue adb reboot recovery
cd into your backup folder
Issue adb push system-data /data/system-data and adb push user-data /data/user-data

Note You have to be very careful with the adb paths. Sometimes it just throws everything into ., sometimes it follows into the sub directory. The correct how-to for this paths is not clear to me now

Ingo

Did anyone else encounter this:

$ adb pull /data/system-data
adb: error: failed to copy '/data/system-data/etc/writable/localtime' to './system-data/etc/writable/localtime': remote No such file or directory

Luksus

@ingo yes, I had the same kind of issue on my FP2 and gave up...

Ingo

Sounds a bit like a dangling link, similar to what is described here: https://bugs.launchpad.net/snappy/+bug/1650688

Rondarius

You have to create the directory of system-data and user-data on the pc and put the files that you pulled from the device into the directory. I did not do this until after I had pulled from both system-data and user-data, I copied all of the files/folders that was pulled in both directories.

Rondarius

HMMMM I bricked my phone. I am back shortly after doing a reinstall of my phone and I am doing a total wipe of the storage.

Ingo

@Rondarius said in Migrate data from device to device:

You have to create the directory of system-data and user-data on the pc and put the files that you pulled from the device into the directory

Yeah, but pulling the files from the device to the PC is the thing that doesn't work.

Rondarius

@Ingo Hmm I didn't get any errors while pulling the files to the pc, I'm on a Nexus 5.

Rondarius

Development branch.

Rondarius

I did a new backup on my phone and tried to migrate to another Nexus 5. The wifi nor the mobile network works, notes, the clock app, the calculator an gallery does not work either. But all my contacts and messages has been imported. I have not tried with other apps.

kwah

Found this topic again after a while, since screen of my bq 4.5 is not responding to touches anymore.

Tried to do backup as explained by @Flohack in Migrate data from device to device. Below are my observations and notes.

Sequence adb reboot recovery followed by adb pull /data/system-data have not copied anything, because it errored out:

$ adb pull /data/system-data
adb: error: failed to copy '/data/system-data/lib/ufw/user6.rules' to './system-data/lib/ufw/user6.rules': remote Permission denied

Added adb root to the mix to handle "Permission denied", and after a bit of copying I've got to the next error:

$ adb pull /data/system-data
adb: error: failed to copy '/data/system-data/var/log/installer/media-info' to './system-data/var/log/installer/media-info': remote No such file or directory

Looks like permission errors can be resolved. Why files are missing?

After digging a bit (cross-referencing results of broken symlinks in recovery and normal environments, looking into mounted filesystems and layout) I think it is because of "dangling" links pointing to nowhere for the following reasons:

Parts of the file system are not available in the recovery environment, because not mounted, like many click packages
There are broken links in the systems (links that are broken also in normal boot) accumulated through its lifetime due to bad behaviors of install/uninstall/upgrade tools and SW in general

All the above leads me to the following:

Looks like adb pull should be run at least in rooted recovery (maybe it should also use -a switch to preserve permissions?)
adb pull cannot handle "dangling" links

So in my experience adb pull is not a good tool to make a backup.

I would really appreciate, if someone could comment on the above and tip better and working ways to backup data so that it can be restored on the other device.

Currently I am looking into the option of creating backup on external sdcard using tar + gzip.

kwah

Here is an instruction that worked for me to transfer data from Bq 4.5 to Fairphone 2

Required:

SD-card
Both device should have SD-card slot
adb tools

Preliminary Steps

Check that your SD-card is accessible on both devices
While device is booted and connected to PC, figure out SD-card info needed for accessing it when device is booted into recovery:
- In adb shell issue mount command
- Note the device that is mounted to /media/phablet/<...>, example in my case
```
<... -removed>
/dev/mmcblk1p1 on /media/phablet/ubackup type vfat (rw,nosuid,nodev,relatime,uid=32011,gid=32011,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks2)
```
  Note that device /dev/mmcblk1p1 is mounted to /media/phablet/ubackup, which is SD card in my case, expect that last part of /media/phablet/ubackup will be different in your case. Make note of the device name (/dev/mmcblk1p1).

Backup data to SD card

If not done before: connect phone to PC while adb is running
Reboot phone into recovery: adb reboot recovery
Acquire root: adb root
Activate shell: adb shell
In the root shell (command prompt ends with # sign)
5.1 Mount SD card with the following command (note that /dev/mmcblk1p1 above becomes /dev/block/mmcblk1p1) :
```
mount -t vfat -o flush,utf8 /dev/block/mmcblk1p1 /sdcard
```
5.2 Backup system-data and user-data partitions (commands below will also create log files, that can be examined for possible errors) :
```
tar -czpv -f /sdcard/system-data.tgz /data/system-data/ >/sdcard/system-data.out 2>/sdcard/system-data.err
```
```
tar -czpv -f /sdcard/user-data.tgz /data/user-data/ >/sdcard/user-data.out 2>/sdcard/user-data.err
```
5.3 Check created archives. The commands below should not produce any output:
```
tar -xzv -f /sdcard/system-data.tgz >/dev/null
```
```
tar -xzv -f /sdcard/user-data.tgz >/dev/null
```
Power down your device (example for adb shell) :
```
shutdown -P now
```

Restore data from the backup on SD card

For me it was repeat of the sequence from the previous section but with the target device connected. The only difference was in the final step.

In principle, external card reader device may require different device name in mount command of step 5.1 options. You can check it as indicated in the Preliminary Steps section above.

Repeat steps 1. ... 5.1 to make SD card accessible.

In the root shell (command prompt ends with # sign)
5.1 Mount as in the 5.1 above
5.2 Restore data:
```
tar -xzv -f /sdcard/system-data.tgz
```
```
tar -xzv -f /sdcard/user-data.tgz
```
Reboot your device

Flohack

TLDR; In case you get pull errors, leave system data out. You will loose all your settings in system-settings etc but the app data is in user-data and that folder must always be pullable without issues. You might want to delete the contents of .cache before to make it smaller...

kwah

@Flohack said in Migrate data from device to device:

TLDR; In case you get pull errors, leave system data out. You will loose all your settings in system-settings etc but the app data is in user-data and that folder must always be pullable without issues. You might want to delete the contents of .cache before to make it smaller...

Well, loosing all settings in system-settings etc. looks like a big deal. One needs to reconfigure everything then.

As far as I understand, system data is not and will not be pullable unless the tools are fixed with respect to handling "dangling" symlinks.

Unfortunately, I had issues with user-data as well.

By the way, do you agree that in the original instruction adb root should be added? I don't know which phone you used as a reference to create the instruction, but I have noticed that adb shell on Fairphone 2 has root enabled by default.

Looks like we start to get requirements for user data lint tool / backup prepare tool (maybe something for UT Tweak):

Cleanup caches (is it safe to remove qmlcache/qml_cache/api_cache and friends?)
Remove "dangling" sym-links
...

Flohack

Hmm I am wondering maybe its your adb version that makes that issue, can you check which one you have? Try adb version...

You cannot remove dangling symlinks, as they are probably used in the live image. I will try again what I did. adb shell should give root on all devices in recovery.

BR Florian

kwah

I used adb from Ubuntu 19.04 repositories:

$ adb version
Android Debug Bridge version 1.0.39
Version 1:8.1.0+r23-5
Installed as /usr/lib/android-sdk/platform-tools/adb

$ apt-cache policy adb
adb:
  Installed: 1:8.1.0+r23-5
  Candidate: 1:8.1.0+r23-5
  Version table:
 *** 1:8.1.0+r23-5 500
        500 http://archive.ubuntu.com/ubuntu disco/universe amd64 Packages
        100 /var/lib/dpkg/status

Concerning root: I had to explicitly request it on Bq 4.5. On FP2 adb shell was with root access enabled by default.

L-00329

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