Ok, here is what I have for you.
rastsaga.zip is the set you want.
You need to change the maincpu ROMs.
game | desc | rom name | region | offset | size |
rastsaga | Rastan Saga (Japan Rev 1) | b04-20.76 | adpcm | 0 | 65536 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-19.49 | audiocpu | 0 | 65536 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-01.40 | gfx1 | 0 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-03.39 | gfx1 | 20000 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-02.67 | gfx1 | 40000 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-04.66 | gfx1 | 60000 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-05.15 | gfx2 | 0 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-07.14 | gfx2 | 20000 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-06.28 | gfx2 | 40000 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-08.27 | gfx2 | 60000 | 131072 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-14.19 | maincpu | 0 | 65536 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-13.7 | maincpu | 1 | 65536 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-16-1.20 | maincpu | 20000 | 65536 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-15-1.8 | maincpu | 20001 | 65536 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-18-1.21 | maincpu | 40000 | 65536 |
rastsaga | Rastan Saga (Japan Rev 1) | b04-17-1.9 | maincpu | 40001 | 65536 |
It's possible you don't even technically have to change all 6, because they are in pairs.
My memory is fuzzy on that, and my notes are not as detailed as I remembered.
When I was in the middle of all my work on Rastan, I thought I would remember everything about it and didn't write some things down. I was wrong.
Changing all 6 is recommended though, as that's how the code was intended to run.
Their positions on the PCB are 14, 21, 22, 23, 24, 25.
You can see they are labeled with blue painter's tape below.
You should only use rev 1 ROMs as my testing has shown that rev 0 have a bug that causes a crash on level 5, in some instances.
I have verified this on legit and bootleg boards and have read other online accounts.
All Rastan romsets will have dumps that end with the same extension.
You are interested in: .7, .8, .9, .19, .20, .21
This is the mapping from the romset to the positions on the board.
b04-13.7 = 21
b04-15-1.8 = 22
b04-17-1.9 = 24
b04-14.19 = 14
b04-16-1.20 = 23
b04-18-1.21 = 25
I hope this is helpful.
Edit: I had read the rom labeled 25 as 15. I have corrected that.