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I've got a 16 GB MicroSD card previously used in a Galaxy smartphone.

What I see now is a disk hardly recognizable by a card-reader. The one that actually could have recognized it shows a disk with around 200MB unformatted space.

diskutil list output:

/dev/disk2 (external, physical):
    #:TYPE NAME    SIZE       IDENTIFIER
    0:             *255.2 MB  disk2

I couldn't get dd to copy more space from it than 200-ish MB (even with the exact number of bytes to copy), and EaseUS data recovery software finds absolutely no signs of a filesystem or any files on this drive.

So, could you please guess:

  • Is it possible to tell the system its actual size (via messing with MBR maybe)?
  • Is it possible that the drive is encrypted by the phone (however, I was not prompted a password at any point).

RESOLUTION: the card appears to be broken at the hardware level. The accepted answer is probably a comprehensive guide for a "regular" case.

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1 Answer 1

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Recovering data

To recover data you can use photorec , or ddrescue

To fix the MBR

You can use testdisk to fix the MBR , or you can delete the existing partition an rewrite the MBR table using GPARTED.

Edit

Open the terminal and type:

sudo testdisk

Select "create a new log file"

Select your micro-sd and press enter

select the partition type

In the next screen, select Analyse

You will get someting like this:

TestDisk 6.14, Data Recovery Utility, July 2013
Christophe GRENIER <[email protected]>
http://www.cgsecurity.org

Disk /dev/sdb - 7794 MB / 7433 MiB - CHS 1023 240 62
 Partition               Start        End    Size in sectors
>P FAT16                    0   2 49     4  66 48      63488 [ARCHISO_EFI]
 P FAT16                  374  87 47   386 148 40     182336 [NO NAME]
 P FAT32                  386 180 41  1023   8 48    9467904

At this point you have the option to select a partition and press P to see your files, and copy them to another storage by pressing C .

When TestDisk finds a partition that it can restore, it is marked in the left column with a P

Hit Enter and then you can try writing the partition to disk ( you can perform a deeper search).

Then you can select writing the recovered partitions to disk

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  • Thanks! How do I tell the system that the actual size of the disk is 16GB without rewriting or deleting anything from it (I mean can constrain my intrusion to the first 512bytes of the drive?)? See, I can only backup those 200MB, and I'm sure the lost data is beyond that space. Regarding the recovery, go-to tools for Windows (EaseUS products) did no good.
    – Igor Shalyminov
    Commented Jun 3, 2016 at 13:26
  • Thanks again! Just to be clear, if testdisk recognizes that my poor microSD drive is only 255MB in size, there's not much I can do to recover the full 16GB?
    – Igor Shalyminov
    Commented Jun 3, 2016 at 15:02
  • If the missing partition is recovered successfully using testdisk you can found the 16 GiB. If doesn't you will recive The following partitions can't be recovered:
    – GAD3R
    Commented Jun 3, 2016 at 16:02
  • I don't understand why you are starting the answer by suggesting photorec while later on you switch to (the much more appropriate) testdisk approach. :)
    – Andrea Lazzarotto
    Commented Jun 5, 2016 at 9:50
  • The first step , it's recommanded to recover the maximum of data , the 2 step is to repair the card (+recover data) , it's possible to delete data by pressing a wrong key .....
    – GAD3R
    Commented Jun 5, 2016 at 10:56

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