I successfully turned off the SIP ALG in a NetGear using this procedure:

Unplug power from unit
Place unit underneath front driver-side tire of your car
Start car, put in drive, remove foot from brake
As car moves forward, hear crunching noise
When crunching noise ends apply brake and place car in reverse
Remove foot from brake
As car moves backward, hear more crunching sounds
Repeat as needed
When crunching sounds have subsided the SIP ALG is successfully deactivated.

-MC