Unforchunately the ODIS (VAG dealer/workshop software) has not any description of the coding bytes and homelink support only 3 bytes to code. The next step was to try to code the UGDO (universal garage door opener or homelink).

Thankfully to googling, I found the next info:

• 35 00 00 - for US cars, with physical Homelink buttons next to the roof control
• 31 00 00 - for EU cars, with buttons
• 25 00 00 - for US, without buttons
• 21 00 00 - for EU, without buttons

After trying each combination, I realized that the first 4 bits are responsible for the count of channels and the second 4 bits for the country. The interesting think is that I got only two kinds of answers: successful or unsuccessful coding results.

But as the coding was discovered, I got the next:

It was when I changed the 25 to 21. When I changed it back (21 to 25).

(Sorry for the language; you can compare it to the previous screen as the order is the same.)

Unfortunately, my remote was still not recognized by the car.

More interesting things was under adaptations, but none of the known authorization codes was working. And because of lack of time, I forget about my idea for some time.