Due to a change in the power protection circuit, the new Mac Book Pro laptop computers will not supply sufficient power over the FireWire bus to initially boot older Saffire and Saffire LE units. Once the Saffire has powered up with the included external power supply attached, the power supply can be disconnected if required. the Saffire can then be bus-powered.
All units above these serial numbers will have no problem booting from the MacBook Pro's firewire bus power.
SFFR10055 (Original Saffire)
SFLE03750 (Saffire LE)