Here is the guide to generate Audi A3 ID48 special chip by using Xhorse VVDI2 VAG key programmer.
Guide:
Insert a common Megamos ID48 chip into VVDI2
Open VVDI2 vag software
Select Transponder Programmer
Select Generate Special Chip-> Auto Detect Chip Type
Select TP25 (Audi-CAN)- Megamos 48 chip
Click on Generate button
VVDI2 generate Audi a3 2003+CAN bus TP chip success.