Last year I bought an M1R. The owner had taken the battery out to protect it from leaking if it went bad. It was in his closet for 7 years. I searched the web, found the factory sysex files. I put in a new CR-2032 battery. Loaded the sysex with MIDIOX (
www.midiox.com) from my computer via midi cables. All is fine.
Peace..