There are out there a number of TV Box that mount this gigabit transceiver instead of the more popular RTL8211F.
Almost all of them work ok at gigabit speed with the Android stock firmware, while deliver a non working (or insane slow) gigabit connection with the Linux Kernel used by Libreelec and Coreelec.
It is not the case of some tv box with this PHY but with 100Mbit line transformers that run only 100Mbit
There are a number of reference to the issue around, like this one:
A (bad) workaround is to force the link speed to 100Mbit. Community and myself have already verified that the dts we use is aligned with the android stock one.
So the only explanation I have is that there are some tweaks in the linux kernel used by the android firmware. I have already tried all the 4 combination of TX delay in the S912 stmmac glue driver, but it does not help, so I am 99% sure that the problem is with the RX delay (RX clock screw) configuration in the PHY.
Using my company email I have already tried to reach out the tv box manufacturer and ZTE in order to try to gather some info, still waiting if I can succeed.
There is absolutely no information in internet about this transceiver, also the ZTE website does not even mention that they make transceiver!
But it is possible that amlogic has some knowledge of this phy. Because of my work I know how this chinese manufacturer work, it is possible that they used this PHY to reduce BOM cost and after having hit design problems, they have asked amlogic for support, so that is why it is possible that they have info on this.
I know that some of you, in particular @chewitt, have contacts with Amlogic, so maybe it is worth to try to see if they know anything.