Please pull-up SELFPWR pin for slef powered Hubs.
Please connect RREF of 649 Ohms with 1% tolerance.
Please connect Power On Reset (POR) circuitry (RC ~10ms) to make sure that all the power supplies are stable before the Hub comes out of suspend.
Please check whether the crystal is up and running.
Please perform continuity tests on the upstream traces to make sure everything is properly connected.
It is recommended to connect decoupling capacitors on the power pins to filter out the noise as in the reference schematics of HX2VL at:
It is recommended to connect pull-up resistors on OVR# pins though they are internally pulled-up to avoid unnecessary current sinking due to nearby EM radiations.
Please go through the Hardware design guidelines of HX2VL for more information at: