Can I re-install firmware for my Meridian 568.2MM?

A slight power fluctuation during a storm caused my Meridian 568.2MM processor to crash. Now there is no sound and it responds in a confused manner. How can I re-install the software / firmware for it without having to pay an arm and a leg?

Also, s it true that Meridian no longer makes available firmware downloads that support their 500 series stuff?

Any advice would be greatly appreciated.