Systems Deployment

We have been UEFI iPXE booting systems for imaging on K2000 for a little over a year now without problems. Every model we have received from Dell has had no problem booting once you disable Secure Boot. We are now trying to deploy the new Dell Optiplex 7460 and I can't seem to get it to UEFI iPXE boot. It detects media presence, "iPXE initializing devices...ok", it gets to "iPXE 1.0.0+ (aa4b0) -- Open Source ..." just fine, but then dumps out

"Could not open net0: Input/Output error (https://ipxe.org/1d6a4698)".

I've tried updating the BIOS to the latest version, changing power settings, but nothing seems to work. I've even tried booting from USB into the KACE environment, but the network still drops out and running "startnet" doesn't initialized the built-in Ethernet. We've resorted to using both USB boot, and a separate USB Ethernet adapter.

All of our other systems can still UEFI PXE boot and Legacy PXE boot just fine to the K2000, just not this model. Our current work around is using a separate USB boot and a USB Ethernet adapter to get into the K2000 environment, but it's just too clumsy for the techs. It moving backwards like servicing the first gen XPS13s. The 7460 does Legacy PXE into the K2000 WindowsPE environment, but can't seem to initialize the network interface, I haven't tried updating the KBE with additional drivers, but I really don't want to resort to Legacy PXE boot, I would like to maintain UEFI PXE for our systems as all the other computers work with it fine.

Has anyone gotten the Optiplex 7460 to UEFI PXE into the K2000?

Any tips or anything I should try?