Further checking, you may refer to below documentation for reference:
And in reference the FAQ http://www.intel.com/content/dam/www/public/us/en/documents/faqs/ethernet-controller-i210-i211-faq.pdf
Section 2.31 What are the I210 SMBus slave addresses?
The SMBus slave address is configured in the NVM. The 7-bit address in the images supplied by Intel is 0x49. For additional details, refer to the NVM settings in Section 220.127.116.11, “SMBus Slave Addresses — Offset 0x03” in the Intel® Ethernet Controller I210 Datasheet.
To obtain further support, there are some information only available on Intel Business Portal (IBP) https://businessportal.intel.com/irj/portal which is protected under a Non-Disclosure Agreement (NDA). You may also contact your Intel Field Representative for access to NDA content.
As this is a design inquiry, you may also find useful information by accessing Resource & Design Center or Intel® Embedded Design Center below:
Hope the above information help.
Thank you for your detailed reply. I had been reading the I210 datasheet and FAQ prior to submitting this question, it's just difficult to sift through 900 pages in the time I have available.
When the I210 datasheet refers to "NVM", do they always mean "iNVM"? I took Section 2.31 to mean that an SPI Flash was necessary to change the default SMBus Address.
As this is a design inquiry, you may also find useful information by accessing Resource & Design Center or Intel® Embedded Design Center below for the support group to further assist you.