I would not worry about it The code is useless , Does not work for FBA .
It works, the problem is that FBA is not loading the data correctly, but the descrambling is correct, i think that fataku's code is better because it works either with 128 KB version and 256, the second doesn't work correctly because the loading routine for this rom is not correct at all, test the fataku version splitting the s1 rom, you'll see that works, the other s1 probs come from the rom itself...
I hope someone can fix the 256 KB s1 rom problem
See ya!!!!