How can I enable external modem functionality on the AT&T IoT Starter Kit (2nd Gen), as mentioned here: http://cloudconnectkits.org/product/lte-starter-kit-2? (See the comparison with the first gen starter kit.) One of the technical guides says that's not supported, but the current sales page says it is - also AT&T technical sales recently steered me to this device - and the embedded linux software seems to be capable of handling it. A linux board connected to the sk2 via usb enables port ttyACM0 and responds to various AT commands, although the external board I'm working with does not recognize the device as a modem. However, assigning an IPv4 address to the sk2's existing ecm0 interface for usb networking, and modifying the iptables to accept INPUT and FORWARD packets, turns this device into a simple router which linux does recognize as connecting to the internet, but changing these settings from their factory defaults seems like "fighting the firmware".
I can probably get this hack to work in a real iot mode - e.g. not connected to a keyboard and monitor - but is there a simpler and more secure way to achieve connectivity from a separate iot board connected to the sk2 via usb? I'm working with a jetson nano, but any solution for a raspberry pi or other iot linux board should also work. Connectivity either as a standard modem or as a usb network connection will suit my use case, I just need to enable internet connectivity over 4g lte. Thanks.