An anonymous reader writes: Across New England, updates have apparently been rolled out to Comcast's Motorola cable boxes that disable the serial port so that Tivo can no longer change channels. My dual-tuner Tivo can still access non-digital channels, but I have to use the cable remote to access HBO and the like. If you're a Comcast user with a Tivo, please let Comcast know you're displeased with this behavior — although they may be working with Motorola to back-out the change. New cable boxes with functioning serial ports will have the serial port disabled after automatically downloading this update. Asking tech support for a "Factory Default Reset" might help for some boxes. Comcast claims to have been unaware of the update and blames Motorola for pushing it out — begging the question of why a service provider would allow a hardware vendor to make changes to their customers' devices without so much as a heads-up?