Apple has issued a graphics firmware update for all 27-inch iMacs in an effort to resolve flickering, yellow tinges and other problems reported by owners of the new computers, which debuted Oct. 20.
The update, applies to the graphics firmware on the ATI Radeon HD 4670 and 4850 graphics cards used by the new iMacs. The update is designed "to address issues that may cause image corruption or the display to flicker," Apple states on the support page.
When reports of the display problems surfaced last week, Apple said it was delaying shipments of the 27-inch iMacs by two weeks. But Apple never said whether the delay was related to the problems with the displays, overwhelming demand for the products, or some other issue.
But Apple doesn't appear entirely confident that the firmware update will resolve the problem. The support page states that if the screen remains black after installing the fix or if flickering continues, iMac owners should contact AppleCare or an authorized service provider.
This morning a thread on an Apple support discussions page, called "New Mac 27inch screen flickering/tearing/shutoff," had 1,550 messages and more than 251,000 views. Other threads also dealt with the display problems, as well as reported problems with excessive noise coming from the displays.
Another discussion thread focuses on the firmware update. "I have a 27-inch i7. I applied the firmware last night. Today I have been working in iPhoto and have seen flickering, one example where the screen has split, and frequent black screens. So ... don't expect the firmware fix ... to fix anything!" said a posting by an iMac owner with the screen name "dambox."