For reference, in the VF3TB/Toy Fighter driver here's what the SH4 writes after downloading it and booting the ARM7.

First the init:

(keep in mind everything's little endian, so e.g. writing 001100a0 means a0 00 11 00 in memory (command a0, parameter 1=11, parameter2=12).

Code
200 to 50
ffffffff to 60
ffffffff to 64
ffffffff to 68
ffffffff to 6c
ffffffff to 70
ffffffff to 74
ffffffff to 78
ffffffff to 7c
0 to 60
18a0 to 400
4b505444 to 10000
0 to 10004
1 to b0
0 to b0
1 to 64
18a0 to 404
1 to b0
0 to b0
e to 68
18a0 to 408
1 to b0
0 to b0
26 to 78
18a0 to 40c
1 to b0
0 to b0

And here's how it starts 1 song:
Code
001100a0 to 410
011100a0 to 414
021100a0 to 418
071100a0 to 41c
061100a0 to 420
031100a0 to 424
2a to 7c
18a0 to 428
1 to b0
0 to b0
ba8 to 42c

and the second song:
Code
001100a0 to 430
011100a0 to 434
021100a0 to 438
071100a0 to 43c
061100a0 to 440
031100a0 to 444
ffffffff to 7c
18a0 to 448
1 to b0
0 to b0
2b to 7c
18a0 to 44c
1 to b0
0 to b0
ea8 to 450

Based on this I'd gather that 0xa0 is some sort of all-purpose setup and 0xa8 actually plays the sequence.