The retained firmware exposes a mode variable for each emulated NIC.  Historical troubleshooting used an explicit Fast mode for a DE500 and Twisted Pair for a DE435 when a guest failed to recognize a card, performed poorly, or passed traffic in only one direction.  Avanti 5.1.0 validation did not establish a universal prohibition on Auto; leave a working configuration unchanged.

The following is an example for a DE500 at EWA and a DE435 at EWB.  Inspect the actual console variables and card order before changing them; do not copy the device letters blindly.

>>> set ewa0_mode Fast
>>> set ewb0_mode Twisted Pair
>>> exit

Use the exit command and confirm that Avanti closes normally so the console parameters are saved in the configured .nvr file.  Restart Avanti and test recognition plus bidirectional traffic.  Record the former value and restore it if the change does not correct the observed symptom.

The symptoms above are retained as historical troubleshooting reports; they were not reproduced as universal Tru64 Tulip-driver behavior in the 5.1.0 qualification work.