Blog/20140304 Samsung Galaxy S2 data recovery

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1 Samsung Galaxy S2 data recovery

A week ago my Samsung Galaxy S2 didn't start up any more, see here. I had just been to Mobile Learning Week at UNESCO, and wanted the pictures back from internal storage, hence reluctant to just wipe completely. (Side note: Some phones don't have a micro sd card slot, but really, I think it's essential. At least it allows you to back certain stuff up regularly, and then if your phone doesn't like you any more, you can pull the sd card and at least have something. But while the SGS2 has an sd card slot, I hadn't set the camera to go to internal memory - one to remember for the future.)

So how do I get access to the internal storage when the phone doesn't boot? It took me a full week of experimenting. Not ideal.

Here are some things that didn't work:

  • Flashing a new ROM / recovery. I don't have access to a PC with Windows to use Odin. Heimdall didn't work on OS X 10.7, and on Linux (on Raspberry Pi) the phone wasn't recognised. (Though see here for how I got this to work.)
  • I was able to boot into stock recovery, which sees external storage, and thus could run CWM v4. CWM v4 (as zip, see clockworkmod recovery site) allowed me to back up the /data partition. However, this goes onto the internal storage, which I cannot access. So app data saved, but still no access to internal storage. CWM v4 couldn't see the external sd card at all.
  • I could also do the same to get CWM v5 (as zip, touch version, again from cwm site), but similar story. However, at least it sees the external storage. While CWM sees the external storage, it does seem to mount it with root permissions, so it's not possible to use adb to pull the data. Also v5 seemed to confuse internal and external storage.

I finally tried CWM 6.0.4.5 (again as zip, not from cwm site). The zip failed verification, so I couldn't install it. However, in v5, there's an option to ignore that, so I was able to run v6. It seems to run fine so far, and the storage is mounted correctly, and I can now pull with adb! So - solution:

2 Solution

Preparation:

  • Download CWM v5 (from cwm site), and put onto external sd card (as zip).
  • Download CWM v6.0.4.5 (as zip, e.g. search on google [1]), and put onto external sd card (as zip).

Then:

  • Boot into stock recovery (Home + volume up + power).
  • From stock recovery, install the previously downloaded CWM v5 from sd card (as zip) (Choose "apply update from external storage", navigate to zip file, and select.)
  • When booted into CWM v5, disable signature verification, and then install the previously downloaded CWM v6 from sd card, i.e.
    • Go to "install zip from sdcard"
    • "toggle signature verification" (Signature Check: disabled)
    • "choose zip from internal sdcard" (actually accesses the external sd card)
  • In CWM v6, you can then mount internal storage (as /storage/sdcard0), and then use adb to pull /storage/sdcard0. (adb will not preserve time stamps, but you can do a "ls -laRe" if you want particular file stamps.
  • You could also back up the system (including /data) to internal sd card.

So in this way I was able to retrieve the contents of the internal sd card. That's all good.

3 What next?

But - the story isn't quite over. I had expected that (once my data was recovered) I could just do a factory reset to sort out the original problem (i.e. the phone not booting). However, turns out that this was not the case. I did a factory reset in v6, and then again tried in v5 (in case there was a problem with the formatting), but the phone still will not boot properly.

However, at least it did turn out that (as far as I can tell), the factory reset did not wipe the internal sd card storage. It does of course wipe the data (/data), but seems to not have wiped the internal sd card (/storage/sdcard0).

For a solution, see here: Flashing Samsung Galaxy S2 i9100 with Heimdall 1.3.2 in OS X 10.7.5. However, when you have done the factory reset, and you are booting again, make sure that you wait - it will take time for all the apps to be re-installed, and the initial device setup screen to appear. However, if that doesn't work, see the next blogpost.

UPDATE: Apparently I am not the only person whose Samsung phone lost data: http://www.dailymail.co.uk/news/article-2580084/Samsung-spokesman-LeBron-James-tweets-phone-crashed.html However, LeBron James seems to have recovered his data much more quickly than I have. Maybe he had help?!


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