Apple on Wednesday posted iMac graphic firmware update 3.0, available for download on its Web site.

In typical Apple fashion, the company offers few details about what’s changed in this release – or even which iMac models the update is targeted for:

“This firmware update fixes a graphics issue that may cause an iMac to hang under certain conditions.”

One solid clue involves the system requirements: OS X Lion (10.7).

So if you’re having an iMac that’s been hanging since upgrading it to OS X 10.7, download this and see if you can install it.