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MicroSD - disconnects after reading bad block

Posted: 24 Jun 2015, 16:48
by pquesinb
I'm trying to recover photos and a couple of movie files which suddenly disappeared from an 8GB Kingston MicroSD card being used in a smartphone (Samsung Galaxy S5). I'm noticing the following behavior:

Data may be read from the card until you hit a bad block, then it's like the card is disconnected, no more data can be read until I physically unmount and remount the card in the card reader. Right now I'm attempting the recovery using a Windows machine but I may switch over to a Linux machine to see if I can pull the data off the card with dd without being disconnected.

Does this behavior make sense to anyone? is this the Windows OS or driver, the card reader (also Kingston), or could this be happening in the card itself?


- Phil

Re: MicroSD - disconnects after reading bad block

Posted: 25 Jun 2015, 06:39
by cgrenier
Yes, disconnection happens sometimes when there are bad blocks/bad memory areas for device connected via USB.
Instead of using dd to copy the memory card, use ddrescue (ie "ddrescue /dev/sdb sdb.dd sdb.log"). Using the log file, ddrescue should be able to resume the recovery even if the disk is disconnected.