Glad you have a workaround. I think the cause is the Windows boot manager certificate change, not the image.

Your golden Optiplex installed Windows with Secure Boot on. Windows servicing then added the “Windows UEFI CA 2023” certificate to that machine’s db, and switched the boot files to a boot manager signed with it. The other Optiplex 3000s only trust the 2011 Microsoft certificates, so they reject that boot manager. bcdboot works because it copies the older 2011-signed boot manager.

Can you confirm with two checks, in admin PowerShell, on the golden machine and on one target?

[Text.Encoding]::ASCII.GetString((Get-SecureBootUEFI db).bytes) -match 'Windows UEFI CA 2023' mountvol S: /s (Get-AuthenticodeSignature S:\EFI\Microsoft\Boot\bootmgfw.efi).SignerCertificate.Issuer

If the golden machine says True and the target says False, that is the cause. A newer Dell BIOS may include the 2023 certificate in its default keys. I am also looking at having FOS add it during the Secure Boot enrollment task.

@ahaeder A final setting - you have to set Bios exit type = GRUB (not the default SANBOOT) or the boot hangs at ‘Booting from SAN device’.

FYI for anyone else running into this issue - I believe the problem was that I didn’t erase the /tftpboot images when I switched from http to https. I’m not really sure why that would matter, but when I did that, then re-ran the server reinstall and selected https, the images got but back in /tftpboot and my hosts didn’t see the mac error anymore.

@ahaeder No:

The idea of fog client is to rename the host based on what you name the computer within FOG, not the other way around.

If you want it to be a specific name, and you have the FOG Client installed, set the wanted name in the FOG UI, and the host will change automatically.