Any progress on this?

Iam trying to do the same thing, but Iam all new to disassembling.

In the "8XC196Kx, Jx, CA USER’S MANUAL"
- Page 350 "CHAPTER 15 INTERFACING WITH EXTERNAL MEMORY"

"The device can interface with a variety of external memory devices. It supports either a fixed 8-
bit bus width, a fixed 16-bit bus width, or a dynamic 8-bit/16-bit bus width"

Did you look at page 71?
- Table 4-1. Memory Map

"After a reset, the device fetches its first instruction from 2080H"

2080-5FFF - Program memory (internal nonvolatile or external memory)

6000-FFFF - External device (memory or I/O) connected to address/data bus (Map area is 6900-B406 in the 06A906018R, 6000-6900 is FF)

See the table for more info

My problem is were to go from here? (I have a long way for sure!)
Never used IDA before so also need to understand how that works (looking at alot of guides)
This has nothing to do with just finding some maps and altering them in winols! (And I know it's a waste of time to disassemble this old ECU, but I want to learn!)