Apple has released three EFI Firmware Updates for 2010-model Macs, including the iMac, MacBook Air, and MacBook Pro. This update enables Lion Internet Recovery on those older Macs. Introduced in OS X Lion alongside the mid-2011 updates to the MacBook Air and Mac mini, Internet Recovery enables access to disk repair or OS X Lion installation options via a broadband internet connection. This is intended for use on a failed hard drive or a blank drive that's never had OS X installed on it.
Together with a series of earlier firmware updates, all Macs introduced from 2010 onward now have access to Internet Recovery features -- with just one notable exception. Even the newest Mac Pro is still excluded from the support list for Internet Recovery.
For both Mac Pro owners and those of you running Lion on a 2009 or earlier Mac, not having access to Internet Recovery isn't the end of the world. If you have a spare external drive, you can either build a recovery disk, or you can roll your own full Lion installer disk.
Apple OS X Yosemite