SCCM - WinPE - "Unable to download PXE variable file" in SMSTS.Log

Question

I am having an issue in Windows PE when trying to build a Dell XPS 8960 via SCCM. The device PXE boots into the WinPE environment without issue, but then it stops before any GUI's are displayed and all i can see is our custom WinPE background. There is nothing else on the screen. It's not frozen, as i can summon command prompt via the F8 key, but the config manager build GUI isn't visible.

I have checked the SMSTS.Log from the machine and i can see the following error:

Unable to download PXE variable file. Exit code=14. Will retry after 15 sec ...

After retrying for 6 or 7 times, it posts a failure log in SMSTS stating:

PxeGetPxeData failed with 0x8004016c

I'm almost certain this is due to missing network drivers in the boot image, and i have already injected every network driver for this model into the boot image already. However, nothing has changed and i am not sure what the issue is.

Does anyone have any ideas?