Perhaps double check LibreELEC Network settings. Perhaps double check cable or switch port.
If no luck, does downgrade to 8.0.2e make Ethernet work again?
If not there may be a physical issue. Could be cable or switch port. Or (hopefully not) MX port.
Good luck (I have the p200 MiniMX-G too)
I wanted to update you all,
Idiot me used the wrong device tree. my box has 1gbit lan and I used 100m for the update.
issue is now resolved.