First off, I know many of us use different processes; DEP, thin imaging and many more. We had an issue with the new iMacs coming in requiring a different build and I wanted to share what we did.
We used the standard tools to get this working utilizing AutoDMG and AutoCasperNBI.
Using the tools mentioned above, we found there was an update at Apple for these new iMacs:
We then proceeded to run AutoDMG and adding the typical Sierra download as we always have done, the required build for these 2017 Macs, we couldn't find a way to download the needed Sierra build. We added this new update package mentioned above, to AutoDMG so it would add the package to the final AutoDMG build. This created a new OS.dmg that was the correct build for the new iMacs, build 16f2073.
We then used AutoCasperNBI to build the new NetBoot image, this worked just fine to build the correct OS and it NetBoots our new iMacs.
I thought I would share this process for those that need to NetBoot, image the new iMacs.