don't ever try to flash the update.img directly to the reader!!! it is sort of a linux live boot image. it's only purpose is to boot up linux from sd card and then flash the reader with images contained inside update.img.
you should take a restore set meant to be installed via USB. It will contain system.img and data.img which have to be flashed to the system and data partitions respectively.
are you able to boot into recovery mode? then it should be possible to safely flash the reader with some standard partition tool via computer / usb gadget connection:
via data transfer mode you won't be able to flash the reader cause it does not give you direct access to flash memory, but to the file system only.