Someone asked me to tune the Game Boy LSDJ ROM like a Japanese Koto. Sure, I said. The scale that this individual requested was the Hirajoshi 2 scale, which is a pentatonic scale made up of the following ratios above a fundamental frequency that is considered to be 1/1:
I've tuned the entire ROM to an A as a tonic note. The process was very similar to previous cases of retuning LSDJ for other purposes. I worked using a spreadsheet, which had the ratios and then calculated the frequencies for each note. Then, the data needed for the Game Boy to generate that frequency was calculated, and converted into hex. Finally, this block of hex tuning data was copied into the LSDJ ROM using a hex editor.
If anyone wants to see the spreadsheet or would like more details, please let me know.