Cyberware is generally portrayed as a technology in rapid development and constant flux. Some characters have cyberware that is in the prototype stage - untired and with lots of bugs remaining. Prototype cyberware also has a tendency to integrate poorly with other cyber, so if one of your implants is a prototype, all your cyber will generally behave as if it was a prototype.
Prototype cyberware fill fail on any snakeyes roll. Whatever action was attempted will also fail. A random cyber system will lock up, and require a Fix-It roll of 15 (10 if in a well-equiped workshop) to repair.