Correcting an sd-card?

[Linux for blind general discussion]

Sounds like you need something like
sudo fsck.fat -a /dev/sdg1
This will check and automatically repair the fat (DOS-style) filesystem on the 
sd card, using the least destructive repair method if multiple methods can be 
used. One problem you may face with such repair tools comes about when the tool 
has to restore what it calls orphaned inodes, unmarked clusters, etc. These tend 
to be stored in files that just have numbers or similar unrecognizable 
filenames. But what it will certainly do is make the files it can repair 
readable once again. Hope this helps..
~Kyle