I received the media link update as an HTC software update on my AT&T One. It was installed very shortly after I bought the phone and was delivered through the "About>Software Updates" section of the Settings menu. The AT&T update, which is delivered through the "AT&T Software Update" section of the Settings menu, was a firmware update that changes the firmware version to 1.26.502.12. It addresses the sensitivity of the Home and Back buttons, and possibly some other minor stuff ... I never did see any official list of what the firmware update did exactly.