Note: Ubuntu 14.04 decided that any serial device plugged into a post-2014 computer MUST be a modem (a type of hardware used with telephone land lines back in the 20th century), and have a hotplug daemon send random AT commands at any new serial device, which confuses the Numato firmware loader. If you are not particpating in the Great Modem Revival, you need to sudo service modemmanager stop. See here for details.
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