Blanking the top-level /dev/sda device like that will trash some thumb drives and make them un-recognizable as storage devices to usb.
I trashed my SONY memory vault that way, and all the various recovery tools to fix against such trashing could not recover it.
As an alternative try just re-partitioning the thumb drive and trash each partition, but be warned writing the partition table may also cause the same problem.
will trash some thumbdrives
Blanking the top-level /dev/sda device like that will trash some thumb drives and make them un-recognizable as storage devices to usb.
I trashed my SONY memory vault that way, and all the various recovery tools to fix against such trashing could not recover it.
As an alternative try just re-partitioning the thumb drive and trash each partition, but be warned writing the partition table may also cause the same problem.
Sam