Yeah, the problem is actually finding an STMicro M27C4001, it was discontinued years ago. (But you can buy them on eBay.) The interesting thing is I checked a few and the ones I checked seem to be the UV erasable variety, not the one-time programmable variety. So in theory, this can be erased and reprogrammed, assuming you have a programmer. So seems possible if you have enough time to figure it out.