While many "free" downloads found on forums can be risky (often containing malware), there are several verified ways to get your code:

Once you have the four-digit code, follow these steps to unlock the unit: myAudi Vehicle Functions - Audi USA

Hold the same button combination again to confirm and unlock. Important Safety Tips Audi Auz1z3 Code Calculator - Facebook

Instead of risking your computer's security with unverified "repack" downloads, utilize these much safer alternatives: 1. Check Your Physical Documentation (Free)