Apple on Tuesday unveiled an update to its iMac line-up, adding Intel's Haswell processors to the all-in-one range. On the very same day, Apple released a firmware update for the new models.

The update, which is an Extensible Firmware Interface update specifically for the late-2013 models Apple announced this week, brings the EFI to 2.1, and is said to fix an issue that can occur when a user attempts to install Windows 7 or Windows 8 using Boot Camp Assistant.

According to Apple's update page on its website, if both an external optical drive and a USB thumb drive are connected to the iMac, it may cause a black screen to appear while installing Windows 7 or Windows 8 using Boot Camp Assistant.

Apple also says that the update ensures that the system will boot by default into OS X after installation of Windows 8.

To find out more about Apple's new iMacs, visit our New iMac 2013 preview.

See also:

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PC Users' Guide to a Mac

iPad Users' Guide to a Mac