so i have been lurking around here for some time and trying to learn on my own but im at the point where i need help. ive been looking up how to do an immo defeat on my 2000 golf ecu because i currently have it in my 90 corrado.

i have really only found a picture that has helped me saying i need to change 12 and 22 to 02 and end of line 020 and to the math of (SUM(2-1) for the check sum, to me it seems like a correct formula but its not working in the car and it fires once and shuts down then cuts off fuel pump prime and spark ect so i know the immo isn't defeated. ill attach both original and what i did files. if anyone could explain what im doing wrong the help would be greatly appreciated.

so if i apply this to mine your saying its (65535 (2-1) - (842) = 64,692 then from there you swap it back to hex, FCB4, then you flip it so its B4FC correct? if so that makes much more sense. thanks for the help, ill see if it works tonight, if it starts then im on to making the mk4 cluster work with the chassis lol