Hi
Situation with Panic Road is a bit complex. There's some memory area used to read unknown data, used for collision/physics calc. So the main goal is to figure out what data is read and how.
There are basically two ways to do it:
1. Trace lines on pcb to find how what data is read, based on the hardware side.
2. Write a test program to run on the pcb, read data and display on screen. Check the data on screen and try to find relation between it and the data in roms.
Mix of both methods is the best idea. It req a lot of work directly with hardware, and writing test programs, depending what's needed. It's hard to do without direct access to the pcb/hardware. I can guide you "remotely" what to do/what to check, write test programs (assuming You have access to eprom programmer, eraser and chips, or programmer + flashroms (to replace program roms). But it's not easy task, and takes ages.
It's the worst scenario. Maybe first simple check (first test program ran on the pcb, or simple look at the pcb lines) can help me underestanding the hardware. Maybe it's simple and easy. But maybe it's not. It's very hard to predict what to do without some simple tests.
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Tomasz Slanina