After upgrading to v4.1.0, I can see the nbi after option booting but as soon as I select it, the mac sits in a frozen state for about 20 seconds before it decides to boot to the already installed OS on the internal hard drive. Any clues on what the problem could be? I even tried downgrading back to v3 and the issue appears to be here to stay. There were no issues before the upgrade to v4.1.0. Has anyone else experienced this?
A bit late to this party, but YES! On a Centos 7 VM running NetSUS 4.1.0, the target Mac can see the NBI hosted within the startup manager and is able to select it, only to have the target mac then delay for ~20 seconds and then boot from the target Mac's primary hard drive. I thought my next step is to verify that the required ports per https://support.apple.com/en-us/HT203437 are open: UDP 67, 68, 69, TCP 80, 548, and TCP/UDP 111, 600-1023, and 2049. (Yes, we could go with either NFS or HTTP; not sure if 548 is still pertinent; seems like it should be 139 and perhaps 445 as well).
Interesting to see that the issue may be NetSUS 4.1.0. Curious if you found an answer to your issue? BSDPy, perhaps?