Back in 2009, a user (abrasive) on an old chiptune site (8bc) posted a Perl script which overwrote both the frequency table and the note name table in an LSDJ ROM. It allowed LSDJ users to break out of the 12TET that LSDJ uses by default, but since the script was written, the LSDJ code changed, and the script broke.
With the help of the LSDJ developer, I have managed to fix the script so that it works with current versions of LSDJ, and I have uploaded it to Github: https://github.com/Dmac9244/LSDJ-Tune.
I hope someone finds it useful; I'm really excited myself to start composing something in Bach-Lehman temperament, and I've already re-recorded all my old chiptunes in it. The difference is slight but I feel that it really helps the chiptune feel more 'alive.' Maybe sometime I'll get a little more experimental, and see what crazy microtonal things I can do with LSDJ.