I add this because it is not listed in known issues even though I have reported it before - if hydra is flashed with ethernet firmware then just connecting other module frezes mainboard right on power up (even without any .net code running). I tried one by one barometer module, humidity & temperature sensor, oled and always with same result - deadlock. It is listed in device manager as “Unknown device” in such case.
Do you have the ENC28 module connected to Socket 3 when powering up the board?