More than two years later and I have similiar problems with NanoPi R76S. Quite unfortunate, with other brands of SBC there is PTP/PHC support, but not with the ones from FriendlyElec.
Someone is working on r8125 kernel driver and I hope there will be a solution soon.

Hi,
I tried every Linux image. But with none there was support for PTP hardware timestamps on the two ethernet ports.
How to find and install drivers supporting this (Alpine preferred)?

regards,
Christoph