NetBoot not working since 10.6 upgrade

Hi all. I recently upgraded from Server 10.5.8 to 10.6.3 (DVD) with software update to 10.6.4. Everything with the migration went without incident. DNS, DHCP, Open Directory, NFS and AFP are all working perfectly (including network accounts, etc.). I just got around to testing NetBoot yesterday and it is no longer working (client never loads booter - just flashes the world symbol for a few minutes before reverting back to internal hard drive). It was fully operational in 10.5.8. I have one NetBoot set I carried over from 10.5.8 and one new Snow Leopard set I created twice while I've been troubleshooting. Tested them both extensively. I referred to Bombich's troubleshooting guide and here's what I've tried with the results, so far...

1.) The initial client BSDP and DHCP requests seem to be working properly, the client just never proceeds with the loading of the booter/kernel :

AAug 5 11:08:45 school bootpd[331]: BSDP DISCOVER [bond0] 1,0:16:cb:c8:e9:43 NetBoot046 arch=i386 sysid=MacBookPro1,2
Aug 5 11:08:45 school bootpd[331]: replyfile /private/tftpboot/NetBoot/NetBootSP0/SnowUtility.nbi/i386/booter
Aug 5 11:08:45 school bootpd[331]: replying to 0.0.0.0
Aug 5 11:08:45 school bootpd[331]: BSDP OFFER sent [1,0:16:cb:c8:e9:43] pktsize 424
Aug 5 11:08:45 school bootpd[331]: DHCP DISCOVER [bond0]: 1,0:16:cb:c8:e9:43
Aug 5 11:08:45 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:08:45 school bootpd[331]: OFFER sent SA-4DADJUNCT 192.168.5.200 pktsize 300
Aug 5 11:08:45 school bootpd[331]: service time 0.176271 seconds
Aug 5 11:08:46 school bootpd[331]: DHCP REQUEST [bond0]: 1,0:16:cb:c8:e9:43
Aug 5 11:08:46 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:08:46 school bootpd[331]: ACK sent SA-4DADJUNCT 192.168.5.200 pktsize 300
Aug 5 11:09:07 school bootpd[331]: BSDP DISCOVER [bond0] 1,0:16:cb:c8:e9:43 NetBoot046 arch=i386 sysid=MacBookPro1,2
Aug 5 11:09:07 school bootpd[331]: replyfile /private/tftpboot/NetBoot/NetBootSP0/SnowUtility.nbi/i386/booter
Aug 5 11:09:07 school bootpd[331]: replying to 0.0.0.0
Aug 5 11:09:07 school bootpd[331]: BSDP OFFER sent [1,0:16:cb:c8:e9:43] pktsize 424
Aug 5 11:09:07 school bootpd[331]: DHCP DISCOVER [bond0]: 1,0:16:cb:c8:e9:43
Aug 5 11:09:07 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:09:07 school bootpd[331]: OFFER sent SA-4DADJUNCT 192.168.5.200 pktsize 300
Aug 5 11:09:07 school bootpd[331]: service time 0.160710 seconds
Aug 5 11:09:08 school bootpd[331]: DHCP REQUEST [bond0]: 1,0:16:cb:c8:e9:43
Aug 5 11:09:08 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:09:08 school bootpd[331]: ACK sent SA-4DADJUNCT 192.168.5.200 pktsize 300
Aug 5 11:09:29 school bootpd[331]: BSDP DISCOVER [bond0] 1,0:16:cb:c8:e9:43 NetBoot046 arch=i386 sysid=MacBookPro1,2
Aug 5 11:09:29 school bootpd[331]: replyfile /private/tftpboot/NetBoot/NetBootSP0/SnowUtility.nbi/i386/booter
Aug 5 11:09:29 school bootpd[331]: replying to 0.0.0.0
Aug 5 11:09:29 school bootpd[331]: BSDP OFFER sent [1,0:16:cb:c8:e9:43] pktsize 424
Aug 5 11:09:29 school bootpd[331]: DHCP DISCOVER [bond0]: 1,0:16:cb:c8:e9:43
Aug 5 11:09:29 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:09:29 school bootpd[331]: OFFER sent SA-4DADJUNCT 192.168.5.200 pktsize 300
Aug 5 11:09:29 school bootpd[331]: service time 0.169816 seconds
Aug 5 11:09:30 school bootpd[331]: DHCP REQUEST [bond0]: 1,0:16:cb:c8:e9:43
Aug 5 11:09:30 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:09:30 school bootpd[331]: ACK sent SA-4DADJUNCT 192.168.5.200 pktsize 300
Aug 5 11:09:30 school bootpd[331]: service time 0.000648 seconds
Aug 5 11:09:52 school bootpd[331]: BSDP DISCOVER [bond0] 1,0:16:cb:c8:e9:43 NetBoot046 arch=i386 sysid=MacBookPro1,2
Aug 5 11:09:52 school bootpd[331]: replyfile /private/tftpboot/NetBoot/NetBootSP0/SnowUtility.nbi/i386/booter
Aug 5 11:09:52 school bootpd[331]: replying to 0.0.0.0
Aug 5 11:09:52 school bootpd[331]: BSDP OFFER sent [1,0:16:cb:c8:e9:43] pktsize 424
Aug 5 11:09:52 school bootpd[331]: DHCP DISCOVER [bond0]: 1,0:16:cb:c8:e9:43
Aug 5 11:09:52 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:09:52 school bootpd[331]: OFFER sent SA-4DADJUNCT 192.168.5.200 pktsize 300
Aug 5 11:09:52 school bootpd[331]: service time 0.178687 seconds
Aug 5 11:09:52 school bootpd[331]: service time 0.000676 seconds
Aug 5 11:10:22 school bootpd[331]: DHCP REQUEST [bond0]: 1,0:16:cb:c8:e9:43 <SA-4DADJUNCT>
Aug 5 11:10:22 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:10:22 school bootpd[331]: ACK sent SA-4DADJUNCT 192.168.5.200 pktsize 383
Aug 5 11:10:22 school bootpd[331]: service time 0.000790 seconds
Aug 5 11:10:24 school bootpd[331]: DHCP REQUEST [bond0]: 1,0:16:cb:c8:e9:43 <SA-4DADJUNCT>
Aug 5 11:10:24 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:10:24 school bootpd[331]: ACK sent SA-4DADJUNCT 192.168.5.200 pktsize 383
Aug 5 11:10:24 school bootpd[331]: service time 0.000633 seconds
Aug 5 11:10:26 school bootpd[331]: DHCP REQUEST [bond0]: 1,0:16:cb:c8:e9:43 <SA-4DADJUNCT>
Aug 5 11:10:26 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:10:26 school bootpd[331]: ACK sent SA-4DADJUNCT 192.168.5.200 pktsize 383
Aug 5 11:10:31 school bootpd[331]: service time 0.000447 seconds
Aug 5 11:10:32 school bootpd[331]: DHCP REQUEST [bond0]: 1,0:16:cb:c8:e9:43 <SA-4DADJUNCT>
Aug 5 11:10:32 school bootpd[331]: replying to 192.168.5.200
Aug 5 11:10:32 school bootpd[331]: ACK sent SA-4DADJUNCT 192.168.5.200 pktsize 383

2.) The TFTP service, with access to the booter file, has also been confirmed as functioning properly (as tested from my laptop to the server as shown here):

$ tftp 192.168.5.10
tftp> get /private/tftpboot/NetBoot/NetBootSP0/SnowUtility.nbi/i386/booter
Received 322301 bytes in 0.2 seconds
tftp>

3.) I've tested both my original NetBoot set (that always worked fine in 10.5.8) in addition to the new Snow Leopard set created in System Image Utility v10.6.4 (the set referenced in #2) and the result is the same; the client sits on the flashing globe and never tries to load the kernel, etc.

4.) I've connected the Xserve to a dumb switch along with a few different test clients, and the result is the same. As a precaution, I also made sure that spanning tree is still disabled on the primary switch.

5.) The client shadow file is being created properly and I checked the privileges on the NetBootClients0 and NetBootSP0 directories and even attempted setting SP0 to Read/Write for "Everyone" (applying to all enclosing items). No help.

6.) I tried setting AFP Guest Access to "Enabled" (though it shouldn't matter).

I'm at a loss. Is there anything else that I might try (short of a reinstall - yikes) on an otherwise perfect 10.6.4 setup? Anyone know it there's a way to completely wipe NetBoot's configuration to force a reset?

Any help would be greatly appreciated! 🙂

Warmest regards,

Ryan