You will see I am writing 2 questions: (1) clone Audi a3 8p chip; (2) 7 bit Cs byte and precode key.
- Clone Audi a3 8p chip
If you need just to clone the chip, Xhorse Mini Key Tool is OK (if it is not smart remote, many tool can clone it).
- How to get 7 bit Cs byte and precode key?
Read this so get an idea what your looking for: How to Find and Write VAG 7th Byte CS with Tango Key Programmer.
I suggest you first learn how VAG Immobilizer works , What is CS, what to do if you have only ECU CS and etc. This will take days and days to tell you.
Do not get me wrong but everyone things I will buy VVDI2, or FVDI clone or etc , press here , press there and done , and make big money . That does not work just like that.