missing tetherrestore

[kerlerm]

Hi Dan.

Cool backup tool. I'm missing a "tetherrestore". :-)
How do I get the contents back onto the phone when I can not copy them over and flash them due to storage space constraints (=same problem inverted)?

Perhaps you could expand on this in the README section? Thanks!

Martin

[dlenski]

Excellent question. I was wondering when this would come up :-)

I haven't pushed any restore code out yet because it's a lot more time-consuming to verify that it's working correctly in all cases. You are right that it is basically the reverse of the backup case (untar or dd).

Let me see if I can put something together this weekend.

[paambaati]

I'd love this too. In the meanwhile, how is everyone else using these backups?

[dlenski]

I have done a few "manual" restores by piping the backup over adb and executing tar on the phone side. (Basically, just what tetherback does in reverse.)

I do hope to write a full-fledged restore tool eventually.

In the meantime, if you have code to contribute, please submit pull requests 👍

[dlenski]

I've started working on this in the tetherrestore branch: https://github.com/dlenski/tetherback/tree/feature/tetherrestore

@kerlerm, @pati610, @paambaati: It'd be great if some of you could please try out test_restore_partition.py and let me know if this completes without error. It's just a quick and dirty test to generate a file full of random data and then push it to the device using the new method of restore_partition(), won't actually alter any device partition.

There are some timing issues that I ran into, and also it appears that tetherrestore is only going to be practical with newer ADB and TWRP which support adb exec-in.adb shell simply doesn't work as an input pipe.

[kerlerm]

Here is the output - it completed without error on twrp 3.0.2 (maguro)

$ tests/test_restore_partition.py /tmp/tmp1pesmyye 512178
ADB: ('adb', 'shell', 'rm -f /tmp/md5in /tmp/md5out 2> /dev/null; mknod /tmp/md5in p')
Restoring image of partition test (../../tmp/test.bin), 0 MiB uncompressed...
ADB: ('adb', 'shell', 'umount /dev/block/../../tmp/test.bin 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'umount None 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'umount /dev/block/../../tmp/test.bin 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'umount None 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'umount /dev/block/../../tmp/test.bin 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'umount None 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'umount /dev/block/../../tmp/test.bin 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'umount None 2>/dev/null && echo ok')
ADB: ('adb', 'shell', 'mount')
ADB: ('adb', 'shell', 'md5sum /tmp/md5in > /tmp/md5out')
ADB: ('adb', 'exec-in', 'tee /tmp/md5in | gunzip -f | dd of=/dev/block/../../tmp/test.bin 2> /dev/null')
  /tmp/tmp1pesmyye: 100%  49.2 MiB/s 500.2 KiB                                                                                            
ADB: ('adb', 'shell', 'cat /tmp/md5out && rm -f /tmp/md5in /tmp/md5out')

[dlenski]

Excellent, thanks @kerlerm!

[paulie-g]

Presumably restoring tetherback's twrp-style backup with twrp itself works?

[paambaati]

Presumably restoring tetherback's twrp-style backup with twrp itself works?

@paulie-g You mean mount the backup directory on TWRP via MTP and use it? If yes, that is great news!

[paulie-g]

No, I mean exactly what I said - taking the twrp-style backup tetherback creates, putting it on internal storage say and restoring it with twrp. It was also a question rather than a statement ;)

[jamy015]

Has anyone verified whether @paulie-g's theory works?

If not, what's 'TWRP-style' about the TWRP-style backups? Would it even theoretically be possible for this to work? (@dlenski)

I can try to test this myself, but I don't have any phones except my main one. If somebody else has a spare phone to test with, I'd like to not potentially wreck my only phone 😛

[Blender3D]

@jamy015 I've done it a few times on my unencrypted Nexus 5 and it's works fine.

[dlenski]

@Blender3D @jamy015,

I have restored from both the TWRP-style and Nandroid-style backups as well, also on an unencrypted Nexus 5 as well as once on a Galaxy S4. (I would feel pretty guilty about calling this a backup tool if it were not possible to use the backups to restore your data :-p)

There are a couple times when restoring the /system partition from the TWRP/tarball backup did not work for me and resulted in a boot loop. However, restoring the /data partition from a TWRP/tarball backup has worked perfectly, as has restoring the /system partition from a Nandroid backup.

I'm not 100% sure why this is: my guess was there is something in the Android bootloader that expects a specific file at a specific offset in the /system partition. If you can shed any more light on this it'd be great 👍.