Apple has updated the firmware that controls its Mini DisplayPort to VGA adapter. The software is available for download from Apple’s Web site.
The Mini DisplayPort to VGA adapter enables these newer Mac models to connect to older analog displays, such as many low-end flat panels or CRT-based monitors. It’s a dongle that connects the Mini DisplayPort connector on the Mac to the display cable.
The update, which updates the firmware in the circuitry on the adapter itself, “addresses intermittent flickering and compatibility issues such as no video on some external displays,” according to Apple.
In order to use it you, you must have the Mini DisplayPort to VGA Adapter plugged into your Mac and a compatible display, and your Mac’s power adapter should be plugged into an outlet.