If it is working do NOT do this, it screws the pooch

 It works fine.  I recommend using a new 8 or 16GB card ($8 on Amazon) for the update.  Simply insert the new card in the DS708 and boot it up.  When it boots up it will error.  Then put the card in the computer and follow the directions above.  It will recognize the serial number.  You'll have to load the device software first since the card is empty but then after that you can install all the makes again and now you have a fresh new card and you still have the old as a backup.  When done, make a backup of the new card, as well. 

Yes