Can you log in locally to the TX2 and find the output of “ifconfig”? If so, then you can find the IP address that way…and the JetPack console or a pop-up will allow entering that. Once the IP address is needed the Jetson is no longer in recovery mode, and the USB cable is no longer used. As a result it implies you can run JetPack at any time with nothing but ethernet connected to work on extra packages. The big trick is that the IP address is only reported automatically to JetPack after a flash…any later run requires you to enter the address manually. Flash itself only understands wired, and thus there is no way to use WiFi for this step.
On the other hand, you can try to use WiFi (not officially supported) if you have manually gone in and set up WiFi. Regardless of if you use wired or WiFi you should be able to do the following, and if the following work, then install packages after telling JetPack the address:
- Ping the address.