Changed the sim on my rooted Google Nexus One today and managed to lock myself out .
Waited for the PUK code prompt to come up but it never did. Apparently there’s none, traditionally on other phones you’s get a dedicated prompt for the PUK code but on the Nexus One you use the “phone pad” instead.
Here’s the walk-through.
1. Call your carrier and have them provide you the PUK code. You might be able to obtain your PUK code from your carrier’s web page also, like mine.
2. Turn the phone on, wait till you see the locked message comes up.
3. Select the emergency call option. Input the the below code through the key pad.
**05* (PUK CODE) * (NEW PIN) * (CONFIRM NEW PIN) #
Your Google Nexus One should be unlocked now.