The agent-tui interface for editing the network config for the Agent ISO at boot time only runs on the graphical console (tty1). It's difficult to run two copies, so this gives the most value for now when there is a graphical console available.

However, when the host has only a serial console, there are two consequences:

1. there's no way to edit the network config
2. console output is frozen while agent-tui is running in the background. If it is not possible to pull the release image, this freeze will last forever and the user will never get to the getty screen on the serial console that tells you about how the release image is not available.

Both situations could be resolved by allowing agent-tui to run on the serial console instead of the graphical console when there is no graphical console.