Apple has issued a new firmware update today to address issues that may cause intermittent display flickering. Earlier today reports had indicated that Apple may have even stopped production of the 27" iMac due to this persistent issue.
Updates the display firmware on 27-inch iMac systems to address issues that may cause intermittent display flickering.
The 27-inch iMac Display Update will update the display firmware on your iMac. Do not disturb or shut off the power on your iMac during this update.
Apple had previously issued a graphics firmware update in December with little success. Today's firmware update appears to address the Display hardware itself. The 27-inch iMac Display Update Firmware is 294KB in size and can be downloaded from Apple's site. Installation instructions are provided here.
