Blessed NetBoot not working on two computers

[wdfraser]

I've been doing some testing with getting blessed NetBoot setup in our environment for maintenance and imaging tasks, however I am having some oddities with two computers in our test environment. I have blessed the NetBoot server through policy as well as manually using bless --netboot --server. All the computers are in the same subnet and point to a netboot server in another subnet. All the other computers restart, and properly connect to the netboot server. Two of the computers seem to completely ignore the bless, and just reboot to the previously selected volume. They never flash the world as if they couldn't find the server. Any ideas on where to start troubleshooting this?

[wdfraser]

I have also verified bless is applied using bless --info --getBoot. I have applied the bless both from within the OS, and from booting from a Lion flash drive. When booting, the machine goes white for a couple seconds then boots normally to the last local drive selected.

[wangl2]

Hi Duncan,
I am having very similar issue to you. The machine goes white for a couple of seconds and boots normally to Desktop. I uses Bless command to NetBoot and my NetBoot server is in different VLAN to clients.
The only difference is this only happen to my new iMacs which were delivered Mid 2011. And the most strange things are, some of these iMacs worked late last year when I NetBoot them. That's why I totally not aware of this problem until this year. I am going to reimage all the new iMacs we got last year in this term break, and realise none of them works with NetBoot. My existing or old iMacs still work fine with NetBoot. And I have already tried updated the Lion server which hosts the NetBoot. I also recreated NBI on the latest hardware. No joy so far!

[Bukira]

i had this on a mac that previously worked, for me it seemed to be related to the latest firmware, try reinstalling the latest firmware or update

[wangl2]

Hi Bukira,
I have already updated to client to the latest patch. It sounds silly but since it worked in the past, I suspect more the new firmware killed it.

[jarednichols]

Clear the PRAM & NVRAM? That's where startup disk info is set. Perhaps clearing it and re-setting the startup disk will do it.

[wangl2]

Hi Jared,
Can you be more specific about how to do that? I came from Windows world not very good at Mac thing. Trying to learn from everyone here in the community.
It happens to all my new iMac, every single one. Do you still think it's the startup disk problem?
At the moment, I placed a second NetBoot server in the same Subnet as Mac clients working. There must be something in these new iMacs that are different from the old ones when they handles NetBoot or DHCP.
Thank you very much!