You could replace it with an EPROM (27C1001). If you don't have an EPROM programmer, you can order a programmed one from https://www.buyicnow.com/it.php?i=379
Yes, if you want an original mask rom, that will take you some searching and time. But if an EPROM will do, I can burn you one with the Last Blade 2 M1 rom data and ship it out to you for say $20 shipped.