Got this from Dish, figured I'd pass it along here:
Subject: Quad LNBF – Special Installation Instructions for the DishPVR 721
Products Affected: DishPro Quad LNBF, DishPVR 721
This bulletin provides special instructions for installing the DishPro Quad LNBF with the DishPVR 721 receiver.
The DishPVR 721 receiver must take a software upgrade (L100 or later) from the satellite before it will work with the DishPro Quad LNBF.
While there are instances when a DishPVR 721 receiver will take an initial software upgrade through a DishPro Quad LNBF, it is not consistent and therefore not the recommended method. The initial software should be upgraded through an LNBF other than a DishPro Quad LNBF using instructions from the DishPVR 721 User’s Guide. It is recommended that a software upgrade from the satellite be accomplished at the dealer’s shop to enable the DishPVR 721 to be installed at the customer’s location with a DishPro Quad LNBF.
Software in DishPVR 721s from later production runs will be updated to include DishPro Quad LNBF installation support.