A little background, we have a lot of iMacs at my organization, different models. We have about 5 different servers running Deploy Studio.
I have found that any of the 14,1 iMacs (late 2013) will only net boot to DS servers that are running OS 10.9+, if I attempt to net boot from a server running OS 10.8.5, using the same image that is hosted on the other servers, the unit will not net boot. The unit stays at the Startup Manager for a few seconds, seemingly frozen, then Apple logo spinning gear, boots to login window of internal HD.
I have read that the TFTP protocol has changed, could this be the reason for the discrepancy of net booting from the same image on different Deploy Studio servers?