I've been wanting to do the same thing for my 96 JWT ECU. All I want to do is modify the K value to work with 615cc injectors but reading their EPROM looks like garbage. I suspected them modifying the address mapping but the "chip" on the 96 is quite complicated... or I'm just not smart enough to decipher it. Reading the ROM from Nissan Data Scan yields a similar ROM address mapping to 90-94 ECUs (I haven't looked at the 95 ECUs but it might be almost-identical to that since the 95 and 96 use 512k bytes). I already had to lose a core charge to get the 96 JWT ECU from them in the first place. I hate the idea of paying JWT so much money for a 96 chip just to change a single value (and possibly a map).
