Same question was asked
here.But more info on how to get it to work can be found
here.You get checksum errors as described
here, but when you use a front end I believe it doesn't care. I ended up running the original in my gamelist with this hack, and then a clone at normal speed. (or vice versa can't remember). That way there are two different versions on my gamelist in my frontend. The fast version (with 3 lives) and the slow version (with 5 lives).