I have a Lexar 1GB micro SD. Neither Windows nor Linux recognizes the device when I plug it in. (The adapter reads other micro SD cards fine.) So I'd like to know what are the most common causes for this symptom and if there's a way to recover. There are pictures on it, and I was hoping to try PhotoRec.

  • corrupted file allocation table
  • someone tried to operate the card at 5V instead of 3.3V
  • electro-static discharge (i.e. zapped it)

If it's a corrupted FAT, you have a prayer of recovery, otherwise I'd say not. Also it won't be easy. You might be able to use a microcontroller to pull the raw data off the card and get the memory image onto your PC for further processing.

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When you say neither OS recognizes the device when you plug it in, do you mean that it's presence is not detected at all (under linux, no messages in dmesg) or that it's not detected as a valid filesystem?

If it's just an invalid filesystem, dd's it to an image file and attempting recovery of that (or at an extreme, just grepping it for jpg headers) could be worthwhile. If there's nothing in dmesg, or assorted errors, it may be harder to do anything.

Posting any output from linux dmesg resulting from plugging it in could be very helpful.

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  • Excellent question @chris. I mean there is no hardware recognition at all. No dmesg output. (Don't know what equivalent of dmesg is in Windoze; would prefer to get it working on Linux so I can use dd(1).) – tbc0 Aug 9 '11 at 17:15
  • Ah well, you can spend time trying to bit bang it in spi mode with a parallel port and see if you get any response at all, but unless what is on there is of supreme importance and you are prepared to perform die-level microsurgery, it's probably gone. – Chris Stratton Aug 9 '11 at 17:36

I've seen some mechanical failures of connector soldering in PCMCIA cards ( same connector as CF but more ins).

You might be able to rework the connector joints and get the device to be recognised.

But it's equally likely that the damage is electrostatic discharge and the whole board is dead.

So it you can, or have friend who can, rework the connector, it might work again.

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