OK, so I've read the threads and support documentation about SIP and netbooting. However, even after using [OPTION], Using the Startup Disk Preference, Booting into the Recovery partition, running Terminal and using the csrutil netboot add commands, I cannot net boot from my El Capitan server.
Even after using csrutil disable, the netboot service is ignored and the on board OS boots as per expectation. I've used Target imaging and even used CasperAutoNBI to create an external boot disk, those work just fine. But netbooting is no longer an option with my El Capitan servers in place.
I surely hope this can be overcome. Even after whitelisting, the bless command is useless. If anyone has figured this out... I'd sure like to know what you did.
Kindest,
-A