Just an idea for an alternative way of getting the chip off.
I have not performed this kind of thing for forensics but have removed
surface mount chips from pc boards occasionally.
The most sucessful, for me, is to get a exacto razor knife and slowly
cut the pins from the board. The solder is soft and pliable. Trying to
get the solder off on multiple pins can be very difficult. Once you cut
away the pins you can trim the solder off by clamping the chip once it
is off the board. Do the same for the good board. Using this method you
minimize the heat applied to the chip, getting the chip off the board,
and a better way to clean up the excess solder.
Any method you do attempt you need to have patience....
-----Original Message-----
From: listbounce@securityfocus.com [mailto:listbounce@securityfocus.com]
On Behalf Of Raymond C. Parks
Sent: 05 January 2007 04:44
To: Michael Edwards
Cc: forensics@securityfocus.com
Subject: Re: Physically damaged SD card
Michael Edwards wrote:
Any tips or ideas for recovering data from a physically damaged SD
flash
card? One of the cards I'm working with has hairline cracks in it,
that
appear to be getting worse with handling. I was able to recover some
data off it at first, but now, no go.
The following is based on personal experience with components much
larger than SD cards, so take it with many grains of salt.
If the cracks are in the PCB, then you could purchase an identical SD
card, very carefully desolder both surface-mount chips (I admit this is
nearly impossible even for experts but I have seen it done), and swap
the one whose data you want onto the good board. Since the difficulty
in removing surface-mount chips lies in doing so without damaging the
board, you could just remove the chip from the bad board. Once you have
that chip, you could implement a breadboard that fulfills the
functionality of the PCB. With all of the latest hardware compilers and
such, that isn't as hard as it sounds, and you could use the duplicate
(still need that) to reverse-engineer the functionality. If the actual
flash memory chip is a standard one, you could just implement a
breadboard that allows access to it via some easier mode than the SD
standard.
All of this would require resources far greater than one would be
willing to expend for vacation pictures, however. I don't know,
off-hand, of any standard kits that might help, although the flash chip
manufacturer may offer development kits that could be adapted.
Ray Parks
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