We recently spun a custom teensy 4.1 board with integrated magnetics for ethernet, but it seems the ethernet peripheral doesn't seem to report link connected for the majority of the boards (some however do in fact connect properly). The schematic for the board follows the Teensy 4.1 schematic exactly for the ethernet, and boards with nonfunctional ethernet also do not function with the official teensy 4.1 ethernet breakout (bypassing the onboard magnetics).

Could there be some caveat/something we're missing here that isn't immediately obvious? All solder joints look excellent both under x-ray and microscope.

Eli