If you're anything like us, your inner-geek revels in hearing rare system beeps while holding down obscure key combos that only occur while updating low-level firmware. While much of those theatrics have since disappeared in the modern era, those of you with 2011 iMacs, Mac Minis, MacBook Pros and MacBook Airs can at least relive some of that nostalgia as you update them to their latest respective EFI firmwares. There's four versions (one for each machine, naturally), yet Apple tells us they all address the same underlying problems, including improving "the reliability of booting from the network" in addition to addressing "an issue that can prevent HDCP authentication" after reboots. Finally, there's improvements pertaining to "boot device selection when a USB storage device is hot-plugged." Direct links to the respective support pages are below, or those seeking to avoid guesswork can simply go on ahead and fire up Software Update. Your call.
AppleiMac 27-inch with Retina 5K display (late 2014)