I have a first gen. iphone, 1.1.4 version, unlocked, jailbreaked, and I updated it via iTunes to get 2.0 firmware ( I know I'm crazy, and I should have never done it...)

I followed all the procedure to downgrade my iphone and now it's back to normal except when it asks for my pin, i fill it in, it works BUT I CAN'T RECEIVE CALLS OR GIVE CALLS OR RIGHT SMS ANYMORE. There are no more bars at the top left corner and it sometimes says No Service!!!

I've already tried to restore it but nothing.

What can I do?
Please tell me my iphone isn't broken!

thanks a lot guys