I was able to modify it for the NTSC-J game so that it executes the payload... but I get no display on my PAL monitor... code seems to work as it shows successful progress for me indicated by drive lighting codes I've added.
Success progress
0 - Short - Short - Short
1 - Short - Short - Long
2 - Short - Long - Short
3 - Short - Long - Long
Failure cases
4 - Long - Short - Short
5 - Long - Short - Long
6 - Long - Long - Short
7 - Long - Long - Long
Don't expect it to work but at least you can test it,
here :
http://www.wiidewii.com/data/yu-gi-oh-ntscj-test.rar