iPXE does not try nic1

[NiKiZe]

By default iPXE does call the autoboot command, which as you can see should try all nics until it fails.
Do try to enter the shell and do ifstat followed by autoboot and see what you get.
You might also want to try this in an embeded script - maybe there is something going on that makes net1 unavailable for a few seconds.

On that page you also have suggestions to retry infinity