Love you too
For anyone that’s interested, the function in question looks like this:
The item of interest here are these opcodes
cmp r0,#0x5A
beq #0x8003FF0
The code is comparing the current song value to $5A which is the title screen music and if it is, branch to 0x8003FF0
By changing D0 to E0, you’re making the code jump there unconditionally
Why all songs don’t act like this, I don’t know