Did you ever get this working? I’m also having troubles with my Nanostation M2. It looks like ubiquity has disabled the option to downgrade to lower versions of the firmware on some Ubiquiti hardware with specific MAC addressses, and since the hotspotsystem works from an older version, it throws an error. Even if you use the TFTP method the device isn’t reachable after flash.
Hotspotsystem’s solution is to install openwrt firmware but after many attempts I still can’t get it working. I think its a combination of issues: this is a new process and support responders have english as their second language… plus its probably a bad time of the year.
Anyway, here ( http://i.imgur.com/UpXpWFk.gif ) is my support thread in hopes that another user with experience in ubiquiti hardware can guide me.
So far I would rate hotspot system’s support team very poorly. I’m not an expert, but come on – the whole point of not setting up my own solution was to make this whole process fast and easy. It hasn’t been either 🙁