The Cupertino-based company is believed to have been working on the update since last fall when early adopters of the new unibody MacBook Pros began experiencing issues when connected to an external display, where the display would sporadically lose signal for a few seconds and flick back on.
Since then, it appears that external display issues have spread to a variety of other new Macs equipped with Mini DisplayPorts, in particular the new Mac mini. There are quite a few threads (1, 2, 3, 4) on the Apple support discussion boards pertaining to similar issues, though not all involve problems when using the Mini DisplayPort to VGA Adapter.
For those users who are connected to an external display via the Mini DisplayPort to VGA Adapter, Apple is quietly distributing an 11.2MB "Mini DisplayPort to VGA Firmware Update" over Software Update that will reportedly update the firmware on the adapter itself.
"This firmware update addresses intermittent flickering and compatibility issues such as no video on some external displays when using the Mini DisplayPort to VGA Adapter on your Mini DisplayPort enabled Mac," the company says in a brief set of release notes. "The Mini DisplayPort to VGA Adapter firmware update will be downloaded to the Utilities folder and will automatically launch to update the firmware on the Mini DisplayPort to VGA Adapter."
In order to trigger the update, Apple says the Mini DisplayPort to VGA Adapter must be plugged into your Mac and a compatible VGA display. The company also says that the Mac's power adapter must be plugged into a power outlet if the Mac is a notebook.
It should be noted that as of press time, there was no mention of the firmware update on Apple's website and only a couple of users have reportedly seen the update turn up in Software Update, mainly those located overseas.