A little while ago I sent my adapter designs off to get fabricated and today they arrived.
I ordered 5 of them as they were nice and cheap but as luck would have it 10 arrived, im not complaining and now I can properly install JiffyDOS in all my Commodore machines
Carrying on with my conversion….
I quickly replaced the graphics for the 2 world names that had been changed.
The first island was renamed to “Fly World” and the second was renamed “Army World”
Both have been restored to their original names along with “The Rainbow Islands” text.
Next on the list was to change that horrible looking main character sprite back into Bub (or Bob).
This looked like it was going to be the familiar task of replacing the graphics and changing the colours to match the palette, I was wrong.
When I changed the sprite graphics back I could not match the colours of the original so the bootleggers must have changed the palette. So where is the palette information stored?
Looking at the MAME source revealed all.
As you can see the palette info is stored in RAM between locations 0x200000 and 0x200fff.
So I went to the MAME debugger and started filling this area of RAM with random numbers until I found the area that changed this sprite palette.
The WORD location for this is at 0x20027C and after trying different values I found one pretty much identical with a value of 001D.
So how do I get this to load into RAM every time? Back to the debugger.
Jumping has some bizarre code at address $386 onwards that sets the palette. Its bizarre in that is performs a series of bitshifts to get the values it wants.
So…
The palette value is stored in ROM at location $23630. It takes the value at this location, does its bitshifting routine and the output of that is its final value.
Seeing how this was done I inserted the value I wanted (1D) and manually working it out backwards until I had a value to replace in the ROM.
The original value was 03DE and my new value needed to be 005A.
After inserting it into the ROM and testing I went from this:
To this:
Time to call it a night.
After playing my RI bootleg, Jumping, for a bit I came to the conclusion that despite being essentially the same game it just didnt feel the same with the crappy graphics that had been squeezed in.
I first started wondering about a conversion when I was fixing the Jumping board up and during my tests I found that a lot of the original graphics were still present.
I started out by doing the easy stuff first, changing the text back from “Jumping” to “Rainbow”. The bootleggers had even changed the credits list to different names, all this was changed back. So far so good.
My next step was to see if I could fix that stupid boot screen that normally says “Rainbow Project”. On the bootleg its just a repeating red pattern.
Armed with a couple of instances of MAME and its excellent debugger I set about looking for the changes.
At location 234E on the original it runs a sub routine which loads the background into memory – jsr $113da.l
On the bootleg, this has been NOPed out. Looking at the code this subroutine is still present, just bypassed.
I re-enabled this sub routine and tested the game.
As you can see it was a partial success but looking in the mame GFX viewer its clear than some of the graphics were replaced to make that crap title screen.
The background is still obviously messed up so went looking for that tile first. I found it at location $B6B and after changing it I had this:
Now, to replace the graphics I have 2 choices. Try and figure out how to manually read the ROMs or use a graphics editor of some sort.
The first option is not really an option at all cause im a little too impatient for that.
The second option is the only real way forward and there are a couple of bits of software available (excluding AGE).
The first is an old MS-DOS program called Turaco and the second is its command line update called TuracoCL.
As TuracoCL doesnt work properly for me I was stuck with Turaco.
The program runs fine in DOSBox and the process of copying the graphics tile by tile is very slow and tedious but I cannot find another way of doing it yet.
Now after a little while I finally got the first part of the challenge done and was happy with the outcome.
Comparing this with the original RI screen showed I had made a little alignment error on the A so I went back and fixed it.
Changing the title screen image is a pretty long boring task so Im actually gonna leave that till last.
Next up is to change a couple of the world names back. “Insect Island” is called “Fly Island” and “Combat Island” is called “Army Island”.
After that I will change the main sprite and the Rainbows back THEN its on to the title screen.
More to come…..
Today my reprint copy of Pier Solar finally arrived.
Ive been waiting a long time for this ever since missing out on the original run a while ago.
The games is a brand new RPG title for the classic Sega Megadrive/Genesis and comes on a technically impressive 64Mb cartridge.
Ive quickly fired it up and it looks great but I cant find my AV cable for the Megadrive and I refuse to play this over RF so ill wait until I get another AV lead, hopefully RCM will have one I can swipe next weekend.
Received this Plus/4 today from eBay. Sold as untested with no PSU and fully expected this to be broken.
The power supply connector is a 4 pin affair that looks similar to the C128 and Amiga but it is not. All is not lost however as if you remove the original connector it can be directly replaced with one from a C64, and that’s just what I did.
The swap was a very quick operation and to my surprise the system fired up with no issues other than some keys on the keyboard need a little more force than others.
I think the SD2IEC is also compatible but I will need an external power supply for it as mine normally plugs into the cassette port of a C64/128 for its power needs.