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Cadillacs & Dinosaurs Bootleg

 

Cadillacs & Dinosaurs Bootleg

Posted by barry on 2 June 2015 at 18:57:48

About a year ago, Bonky0013 sent us a dump of a bootleg of Cadillacs & Dinosaurs. I didn't have much time to look at it when it was submitted, and I have only just remembered to revisit this!

This bootleg has the Q-Sound hardware replaced with MSM6295 samples (with a new Z80 program too), similar to the Dinosaur Hunter bootleg. An image of the board can be seen below;

Cadillacs & Dinosaurs bootleg PCB

The board also has a PIC16C57 chip on it (no dump of the program data due to protection though). We have seen this used to replace Q-Sound hardware before, but since we have a Z80 program ROM driving the MSM6295 samples, this is obviously not the case here.

The board also has the graphic ROMS scrambled in a different format than we have seen before. I had this descrambled last year though when I originally looked at this.

The program ROMS are also in a different format. Once I had these loading in the correct order I got the following error on-screen;

Cadillacs & Dinosaurs bootleg boot error

The game was writing a value of 0x04 to 0x5762b0, and then reading from 0x57a2b0, before crashing. This seems to be protection related (and maybe something that the previously mentioned PIC16C57 does?). I looked at a disassembly of the code;

Cadillacs & Dinosaurs bootleg disassembly

Following this through, the game reads from 0x57a2b0, and stores the value in D0. It then checks the value in D0, to see if it is $404. Returning this value is enough to get the game to boot and work properly.

Cadillacs & Dinosaurs bootlegCadillacs & Dinosaurs bootleg
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