This will only set you on the path, I'm sure, (I have an 01/Wfd & don't really KNOW the M1's requirements) but the factory programs in MOST Korgs are set in ROM and can be re-accessed by doing SOMETHING such as holding down two buttons when you switch it on, the Bank 1 and 4 buttons, perhaps.
RUN to Korg.com and ask for that reset procedure. I'm sure the process for their whole LINE is sitting on the receptionist's DESK! Good luck with it and keep a calendar handy with that new battery installment date on it!