john smith wrote:
Unfortunately, the Magellan Explorist 300 has no provisions for updating
firmware or software.

With your possible loss limited to $90, it might be worth it to open the
thing up and see if has a place on the board for a USB connector (or
similar) for updates. They may have been smart enough to both leave out
the connector AND change the firmware to not listen to the USB interface,
but sometimes you can get lucky.

Matt Roberds