Connect with us

Reading erased flash memory

Discussion in 'Electronic Design' started by PeterH2072, Dec 9, 2004.

  1. PeterH2072

    PeterH2072 Guest

    I have a SD flash memory card [256 meg] that's been accidentally erased. The
    original data on the card is extremely important and needs to be recovered.
    Does anyone know if this is possible? The forensic computer services I've
    contacted suggest it might be but they aren't sure. Other than trying to open
    the package non destructively and possibly scan the chip with an ATF
    microscope ...looking for residual charges, does anyone have a suggestion?
    Thanks, Peter
     
  2. John Larkin

    John Larkin Guest

    If it's file structured, maybe only the directory has been erased. So
    the data may still be there in cluster-sized blocks, which you could
    read and try to put back in order somehow. If it's all erased, it's
    gone.

    John
     
  3. Typically it's in FAT format on the card. Perhaps Norton Disk Doctor
    might work on it. In DOS files are erased by just clearing the first
    byte of the name to a null, IIRC, so provided you can supply that
    character all the rest of the data may still be if (if it has not been
    overwritten).

    I recall getting files back once with a program called UE or unerase
    or something like that.


    Best regards,
    Spehro Pefhany
     
  4. Mac

    Mac Guest

    If the files were erased by the operating system, there is hope. If the
    flash memory was erased at the hardware level, you are on your own.

    Anyway, before you do anything else with the "disk," you should be able to
    copy it verbatim and work with the copy instead of the "disk" itself.

    You could get one of those standalone live CD's for linux, and copy the
    entire CF card using the unix command "dd."

    Maybe something like this:

    dd if=/dev/sd0 of=<name_of_output_file>

    The resulting output file will be the same size as the disk capacity, and
    will just be a sequential dump of every byte on the disk, in order.

    Then if you want, you can take another CF card and use dd the other way:

    dd if=<name_of_output_file> of=/dev/sd0

    Do this very carefully, then put the card in a locked cabinet somewhere or
    send it off to a professional data recovery place, or whatever.

    Obviously this is not the forum to discuss this sort of thing, but I'm
    sure you can find information about this on the WWW. The key term is
    probably "computer forensics" or something like that.

    Good Luck!

    --Mac
     
  5. Mark Jones

    Mark Jones Guest


    Indeed, the ATA specification is markedly similar for IDE and SD
    devices. At least I think it is SD devices. Is it CF? Anyways, goto
    www.t13.org and look under documents, you can find ATAPI-6 datasheets
    for the ATA/SD protocols. (Older specs might be easier to read
    actually, less clutter.)

    -M
     
  6. James Beck

    James Beck Guest

    I recovered one for a neighbor that wiped out his kids birthday party
    that they had in Italy with the family. He was in a panic, reminded me
    of Daffy Duck when he made the egg disappear. I used a program called
    oo_unerase. Worked just fine.

    Jim
     
  7. Spajky

    Spajky Guest

    http://www.active-undelete.com/
     
  8. Guest

    If the data are photos, this product works very well.
    http://www.datarescue.com/photorescue/
    I've had it for a couple years and it has bailed me out a couple of
    times. Deleting files or even formatting in a camera will not overwrite
    the data. I bought a used (thought it was new) CF card on eBay and
    found a whole bunch of pictures from the previous owner.
    GG
     
  9. Rich Grise

    Rich Grise Guest

    This ep?

    Right under "Sport Chumpions":
    http://www.wiseacre-gardens.com/buttons/wb.html#Sport Chumpions

    WB340 THE HENPECKED DUCK
    19410830, LOONEY TUNES
    CHAR: DAFFY DUCK;MRS. DAFFY DUCK;PORKY PIG
    DIR: ROBERT CLAMPETT
    SYNOP: DAFFY & THE MRS GO TO DIVORCE COURT AFTER HIS MAGIC TRICK
    MAKES THEIR EGG DISAPPEAR AND HE TRIES TO SUBSTITUTE A DOORKNOB

    I can't say as I've ever seen that one.
    Who in the heck is "Mrs. Duck?"

    And I thought it was Sylvester who was famous for being "Dethpicable"

    Thanks!
    Rich
     
  10. K8JLF

    K8JLF Guest

    I've used a similar thing called photrecovery for digital media. I have it
    installed on my machine right now. If I can find the installer, I'll be happy
    to send it to you.
    I've used a similar thing called photrecovery for digital media. I have it
    installed on my machine right now. If I can find the installer, I'll be happy
    to send it to you.
     
  11. James Beck

    James Beck Guest

    That's the one. He is cast as himself and the little "lady", if memory
    serves.

    Jim
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-