Sky broadband embed user login credential in their routers. If you want to use a third-party router, you have to use Wireshark to sniff it out¹⁾. Here is a summary of what you have to do:

1. Connect to your SkyHub using an RJ45 cable.
2. Fire up Wireshark, set capture filter to “udp port 67 or udp port 68”.
3. Unplug the RJ11 (DSL) cable.
4. Copy the captured packet as printable plaintext.
5. You will see a string that looks like “xxxxxxxxxxxx@skydsl|yyyyyyyy”. Your username is xxxxxxxxxxxx@skydsl, and your password is yyyyyyyy.

The modulation settings should be²⁾:

The whole point of extracting user credential is to make it work with OpenWRT. You might want this³⁾. Please note that there are apparently two ADSL annexes⁴⁾.

Finally you definitely want to delete all the existing ATM bridges. Otherwise your ADSL won't connect.