I don't have a data plan, so instead, I timed with Wifi and Data off, until I got an error.
Then, I turned on Wifi, and turned off (while it was checking for update on Zune) the Wifi one second before, and it worked...the FIRST TRY!
1. Debranded to 000-88
2. Follow instructions on first page, but this time turn off data connection and use Wi-fi instead. (For those without Data)
3. Time Zune Update while Data Connection is off and Wi-fi is off until it gets the error code (when Zune times out or network error comes up).
4. Get the time and now turn on Wi-fi, and wait until it connects.
5. Check for update again.
5. Now turn off Wi-fi a second earlier than what you had timed before.
Try it ... NOW!