Ahhh - I guess I could have been more informative!
Option 7 does delete the firmware and does leave the Reader showing the message you described. When you connect to PC and run the Sony Updater, however, that reloads the Sony firmware and then you run the Customiser (all without affecting your on device library).
I fell into the same trap - delete the firmware then for some unexplicable reason tried to re-set and when that didn't work all logic and reason left me! I resorted to a plea on this board for help (which I received), plugged in and ran the Sony updater and all was well.
It was only when I had the reader running again and thought about it that my one sensible brain cell hiding in among the billiions of non-sensible ones piped up and pointed out that as I had deleted the firmware how could I expect the reader to work at all until I had reloaded!
Sorry for the panic attack...
David