Comment 1 for bug 1666670

That's an input/output error, it means there was an error writing to the
kindle disk. This typically indicates that the disk is close to failing.
You may be able to get more life out of it by either resetting the
kindle or reformatting the drive. A bit of googling should get you
instructions on how to do either. Be aware that doing so will delete all
data on the Kindle.

 status invalid