iMac EFI Update 1.7
This update enables Lion Recovery from an Internet connection and includes fixes that resolve issues with Apple Thunderbolt Display compatibility and Thunderbolt Target Disk Mode performance on iMac (early 2011) models.
For more information about Lion Recovery, please visit http://www.apple.com/macosx/recovery/.
The iMac EFI Update will update the EFI firmware on your iMac computer. When your iMac restarts, a gray screen will appear with a status bar to indicate the progress of the update. It will take several minutes for the update to complete. Do not disturb or shut off the power on your iMac during this update.
Boot ROM or SMC Version Information: After iMac EFIupdate has successfully completed, your Boot ROM Version will be IM121.0047.B1D