Apple has released a firmware update for its early 2004 1.8GHz G5 Power Mac systems.

The update "improves the reliability" of the Mac, "especially after it has been inactive for two hours".

The company warns the 900K update which is available from its support website is: "Only for the 1.8GHz, single-processor Power Mac G5 (Late 2004) computer and supports installation on Mac OS X 10.4.3 or later."

It adds: "Once the update begins, do not cancel or interrupt it. The update takes over one minute to complete. During the update, the Power Mac fans run at full speed. They return to normal once the update is complete."

A firmware update for this model of Power Mac running Mac OS X 10.3.9 is also available.