Legacy PXE on XL710: PXE-EC8 and Above-4G BAR Placement
Source case and error
An SA5112M4 with an XL710-10G adapter could not PXE-install its OS using legacy boot while the BIOS Above 4G option was enabled.
PXE-EC8: !PXE structure was not found in UNDI driver code segment.
PXE-M0F: Exiting Intel Boot Agent.Case workaround
The source disables Above 4G in BIOS for that legacy-PXE configuration. Verify the matching BIOS/adapter firmware and other devices’ resource requirements before changing it; systems with large PCIe BAR requirements may depend on above-4G allocation. This is not a recommendation to disable Above 4G for all PXE or UEFI deployments.
Intel explanation
The checked Intel note says the boot agent cannot locate the required !PXE structure. It lists conventional-memory/PMM corruption or allocation issues and a memory BAR above the 4 GB boundary as possible causes. The error alone does not prove one cause. The source’s blanket statement that “PXE does not support above 4G” is therefore qualified to its legacy boot-agent case.