Hello,
I have exactly the same problem !
Yesterday, I update one iMac with apple store. When finished I Tried to upload image and can’t boot on PXE. It’s freezing.
I tried this morning to download image on another iMac and it works.
I think it’s a bios update in the lasts macOs updates who makes the problem …
@george1421 We have 30 iMac 14,1.
Don’t work :
ROM : IM143.0118.B14
SMC : 2.17f7
Work :
Rom : IM143.0118.B01
SMC : 2.17f2
another work :
Rom : IM143.0118.B13
SMC : 2.17.f7
@george1421 if it can help. I boot on snp.efi. ipxe.efi never working on my machines.
@sebastian-roth Just saw your message ! I will try next week 
@sebastian-roth Just saw your message ! I will try next week
@george1421 if it can help. I boot on snp.efi. ipxe.efi never working on my machines.
@george1421 We have 30 iMac 14,1.
Don’t work :
ROM : IM143.0118.B14
SMC : 2.17f7
Work :
Rom : IM143.0118.B01
SMC : 2.17f2
another work :
Rom : IM143.0118.B13
SMC : 2.17.f7
Hello,
I have exactly the same problem !
Yesterday, I update one iMac with apple store. When finished I Tried to upload image and can’t boot on PXE. It’s freezing.
I tried this morning to download image on another iMac and it works.
I think it’s a bios update in the lasts macOs updates who makes the problem …
I will try your kernel tomorrow. I need to find a solution because my image are still in raw… 124Gb X 15 surface it’s a day to deploy with only one adapter 
@wwarsin I just change bzImage file in the directory after downloading it in fog sourceforge…
Imaging and deploy works but he make a raw image. I will try to set compression as default to see if it’s better …
finaly it works for me with 4.2.3 kernel manualy installed.
Same problem on my Surfaces. I have menu but when I make task. Network device not found
I run svn 5612.