The safety bolts have been engaged or disengaged. This corresponds to the underlying state imposed by the @bolts command. If the bolts are on, then peripherals should be locked in place (@detach=n in RLV); if they are off, then the detachment restriction should be released (@detach=y). The automatic bolts setting (release when powered down) is handled by the controller, so it is unnecessary to check whether the system power is on before reacting to the bolts message over the light bus.

This message is sent to newly-authenticated active devices immediately following the add-confirm message.