I just recently starting having an issue with the Notes application corrupting files on my N810's internal 2GB card.

I can vi /media/mmc2/tmp/foo.txt, then make and save changes, and cat the same file all from the CLI. I can then open foo.txt inside the Notes app, view the edits, do not make any changes and close Notes. No issues. However if I make any edits to foo.txt within Notes app, then save, the file is somehow corrupted. I can not reopen it in Notes (shows a blank document).
cat /media/mmc2/tmp/foo.txt
gives error message:
cat: read error: Input/output error

Any suggestions of what I should look for to troubleshoot?
Is the mmc2 a FAT volume? (it's not listed in /etc/fstab) I ask because I can't run chown or chmod on files in mmc2.