Unable to PXE Boot via Thunderbolt 3, USB-C NIC, USB NIC

[natelindberg1]

Has anyone been able to successfully PXE boot an Elitebook x360 1030 G2 with any consistency using a Thunderbot 3 dock, USB-C or USB NIC?  I am using SCCM current branch, and have no issues PXE booting anything else.  However, this model, I've been tinkering with for nearly 6 months on and off, and sometimes PXE works, sometimes it doesn't.  Currently, I've changed the following in BIOS Setup:

1.  Advanced --> Port Options -->  Require BIOS PW to change TBT SL -- OFF

2.  Advanced --> Port Options --> Thunderbolt Security Level -- PCIe and DisplayPort - No Security

3.  Advanced --> Boot Options --> Fast Boot -- OFF (Tried with this setting OFF and ON)

4.  Advanced --> Secure Boot Config --> Configure Legacy Support and Secure Boot --> Legacy Disable Secure Boot Enable

(I've tried Legacy Enable and Secure Boot Disable also)

In setting #4 above, if I set Legacy Disable/Secure Boot Enable, the client attempts to contact the WDS server, but just endlessly reboots back to the HP Startup menu (normally requires F10 at boot splash).  If I change this setting to Legacy Enable/Secure Boot Disable, the client attempts to PXE boot, PXE boot fails for no apparent reason.  (We are using Unknown computer support, machine is currently not in SCCM).  If I set both Legacy and Secure Boot to Disable, I get the endless reboot back to HP Startup menu.

Does anyone know how to get these things to boot consistently into SCCM OSD?  I've gotten them to image several times before, and even exported the BIOS settings from one machine that did successfully image, and replicated it on others, only to get the endless reboot into the HP Startup menu. 

I've verified that all the drivers I need are in the boot images, but that would be a moot point considering I have successfully imaged them before.

BIOS Version P80 Ver 01.19

Any help would be much appreciated!