A board we have designed has an i210 with external flash.
The design is a copy of a working design.
The Flash is blank, programming fails, note that device 2 and 3 are the known good designs on a PCIe mezzanine.
FS0:\EEUPDATE\TOOLS\EFIx64\OEM_Mfg\> eeupdate64e.efi /nic=1 /mac=000D26570001 /d I21
Using: Intel (R) PRO Network Connections SDK v2.30.2
Copyright (C) 1995 - 2017 Intel Corporation
Intel (R) Confidential and not for general distribution.
NIC Bus Dev Fun Vendor-Device Branding string
1 6 00 00 8086-1531 Intel(R) I210 Blank NVM Device
2 11 00 00 8086-1533 Intel(R) I210 Gigabit Network Connection
3 12 00 00 8086-1533 Intel(R) I210 Gigabit Network Connection
Unable to initialize adapter 1 code c86a2002
Adapter initialization failed