Apple has launched a host of additional software updates beyond the MacBook Pro patch distributed earlier today. Central are two firmware updates for the 27-inch iMac: EFI FW Update 1.0 and SMC Firmware Update 1.0. The former deals with high CPU use when playing audio through the headphone jack, as well as instances in which the backlight does not turn on with the computer. The SMC software copes solely with the compatibility of Target Display Mode.
