fix n80 under warranty, firmware concerns

I used nss and reflashed my n80 to generic firmware. However, my speaker has decided to die and I want to take it to a service centre and get it fixed, it's only a year old and apparently Nokia offer 2 years warranty.

How do I go about this then? Do I just change the product code back to what it was originally and send it in, or am i truely stumped?

Any advice would be great! 😃