MTK830 + RTL8221B-VB-CG 2.5G question

I solved this by porting the driver from WAX206 and setting the PHY to Rate Adaptor Mode and setting it to a fixed link in the device tree. You can see my post here.

If you are not using TP-Link XDR6086 or TP-Link XDR6088, you will need to change the PHY register number from my code because it just hardwired it.