DIY hack: unlock mobile phone

I just unlocked my Nokia mobile phone (model 3510i) for free! Now I'm no longer stuck with O2, and can use it with any service provider—at least that's my understanding. So far it works with my girlfriend's Orange SIM card. Now I'll have to try it out when I get to Berlin next month and see whether a German SIM card works as well.

The way I did it is with a free service on a Swedish website called tycktill. You put in your model number, country, operator, and your phone's serial number, and the site generates a code that will unlock your phone. Then you remove the SIM card from your phone, turn it on, and enter the code.

You only get 5 tries to do this before it becomes harder to do and you have to take it in to a shop to have it worked on. So make sure you enter the numbers correct! The first time I did it, I entered the phone's serial number wrong, so of course it didn't work.

UK shops charge 5-10 pounds to do this, but it's not clear to me why they're authorized to do it, while it seems individuals are not. I'm not sure if this violates the user agreement or anything, but from everything I've read, the service providers don't provide much help in unlocking phones—and viewed in terms of their self-interest, it's understandable.

For another's experience with unlocking a phone (albeit from 2003) read this O'Reilly blog post. Apparently books like Nokia Smart Phone Hacks will also tell you about how to do this. And there's another source of codes and set of instructions on ihacked.com.