Since you have at least one working message, 0x202, and the ability to disassemble the code, one thing to try would be to search for spots in the code where tha

Since you have at least one working message, 0x202, and the ability to disassemble the code, one thing to try would be to search for spots in the code where that gets used as an operand or gets loaded from memory. Unless they use a switch statement (unlikely if the codes are so far apart), there’s likely to be an “if code == 0x202” somewhere that would help narrow down the input handling code. If you’re really lucky, all the other valid codes will be sitting in the same function, which (if nothing else) will make your fuzzing efforts a lot more targeted.