NetBoot Images not "seen" by MM / MBA when booting with ALT without any local bootable Volumes

Hello Community!

I ran into a very odd Problem trying to start Production and Service Mac Minis or Mac Book Airs from our NetBoot Server holding the ALT Key while the Startup Chime sounds. Image selection is working fine if a local Volume is present. When no local bootable Volume is available the Macs will (in 90% of the Cases) stop responding at the point where the Bootpicker should show all available NetBoot Volumes. The dropdown menu for choosing a Wireless Network is popping up but after that the spinning wheel next to it stops and the Mac wont recognize any input from mouse or keyboard.

The EFI Startup environment is not totally stuck in these cases though, cause sometimes when you restart the NetBoot Service on the Server the NetBoot Volumes will popup on the clients screen.

If you hold the clients "N" key instead to Start Up from the Servers Default NB Image it works like a charm. Also all the other Mac Models have no problem at all Netbooting using the Bootpicker.

Among other things I already tried the following:

- changing NBI index numbers

- shortening Image names that are sent out by the Server at the BSDP ACK[LIST] step to reduce the packet size

- deactivating all Netboot Images but one

- setting up a second netboot Server and transferring half of the Images to it

the Netboot Log shows that the following client - server communication is repeated over an over:

Oct 10 16:58:47 macimgsrv.intern bootpd[20296]: DHCP INFORM [en0]: 1,10:dd:b1:ea:d1:e5

Oct 10 16:58:47 macimgsrv.intern bootpd[20296]: ACK sent <no hostname> 192.168.2.112 pktsize 300

Oct 10 16:58:48 macimgsrv.intern bootpd[20296]: BSDP INFORM [en0] 1,10:dd:b1:ea:d1:e5 NetBoot1271 arch=i386 sysid=Macmini6,1

Oct 10 16:58:48 macimgsrv.intern bootpd[20296]: NetBoot: [1,10:dd:b1:ea:d1:e5] BSDP ACK[LIST] sent 192.168.2.112 pktsize 364

Oct 10 16:58:48 macimgsrv.intern bootpd[20296]: DHCP INFORM [en0]: 1,10:dd:b1:ea:d1:e5

Oct 10 16:58:48 macimgsrv.intern bootpd[20296]: ACK sent <no hostname> 192.168.2.112 pktsize 300

Oct 10 16:58:53 macimgsrv.intern bootpd[20296]: BSDP INFORM [en0] 1,10:dd:b1:ea:d1:e5 NetBoot1271 arch=i386 sysid=Macmini6,1

Oct 10 16:58:53 macimgsrv.intern bootpd[20296]: NetBoot: [1,10:dd:b1:ea:d1:e5] BSDP ACK[LIST] sent 192.168.2.112 pktsize 364

As a next step I thought of transfering DNS, DHCP and NAT Services to another Machine, although i dont know if that will help.

If you had the same problem or know anything that might help to solve it, i would be very happy if u share your knowledge with me 🙂

as i am starting to get insane on this one 😉

thank you in advance,

Colin Andrew