The DLC for Fight Night Round 4 was released in several waves, significantly expanding the game's depth. According to EA News , key releases included:
You are looking for a file that is essentially "abandonware." EA no longer sells it, and they no longer host it. Finding the .pkg is the only way to restore the "complete" roster of the game, but it requires a hacked console or emulator to make it work. fight night round 4 dlc pkg
Added heavyweight legends Evander Holyfield , Sonny Liston , and Bernard Hopkins . New Gameplay Modes The DLC for Fight Night Round 4 was
Included a new training gym, gameplay sliders, and an alternate version of Sugar Ray Leonard (Xbox exclusive via Pizza Hut). The Champions Pack (August 2009): Added Oscar De La Hoya , Vitali Klitschko , and Wladimir Klitschko to the roster, along with alternate versions of James Toney George Foreman Added heavyweight legends Evander Holyfield , Sonny Liston