I flashed the latest L4T sample rootfs + BSP + Orbitty carrier board BSP to my TX2 (note: without using JetPack), which completed successfully. I attached the device to my host with a micro-USB cable and my host sees the L4T-README mass storage device, the virtual serial device, and the virtual network adapter it provides.
I can ping the TX2 at 192.168.55.1, and I can ping it at the IP address it receives from my network DHCP server. In both cases the TX2 is responsive.
However port 22 is closed on both interfaces. And the serial console shows nothing, so I cannot log in that way either.
Is there an additional step I need to do when I flash this way to get SSH and serial console access?