Yes, it's pretty much sure HP-UX, you can see it in banners several times throughout booting. Also this thing being made by HP using HP custom hardware you can

Yes, it's pretty much sure HP-UX, you can see it in banners several times throughout booting. Also this thing being made by HP using HP custom hardware you can be quite sure that it runs HP's Unix. Since this device is still not rooted I don't have access to a command line... yet. There's a telnet daemon listening on the network interface, but that's it (I didn't crack the passwd entry yet).