In iW-RainboW-G36M SOM, VCC_3V3 serves as the main power and also supplies to Ethernet PHY, so it is not possible to independently disable power to the Gigabit Ethernet PHY.
If the Gigabit Ethernet PHY interface is not required, it can instead be isolated at the hardware level.
Based on the requirement, the SOMs with different orderable part number can be provided.
For further inquiries, please get in touch with mktg@iwave-global.com
Please find the detailed G36M product information in the below link,