How to unlock your Sony Ericsson A2/DB3150/DB3210
What it does:
Resets Phone Lock code to '0000'
Unlocks SIM Locks (Not 'SIM Protection')
How long time it takes:
Under 5 minutes.
What you need:
Sony Ericsson USB Cable (DCU-60)
Aerix Tool (DOWNLOAD: HERE)
Gordon's Gate Flash Drivers (DOWNLOAD: HERE)
How to do it:
1. Install 'Gordan's Gate Flash Drivers' if you haven't already.
2. Register an account here. Confirm your email address.
3. Run 'Aerix Tool' (aerix.exe).

4. Click 'Settings' and enter your username and password you registered earlier. Click 'Ok' when you are done.

5. Select your model above 'Phone Type'.

6. Click on the 'Unlock' button, then remove and insert your battery and connect your phone via USB cable (DCU-60) holding '2+5' buttons simultaneously.
When you see 'The action reported success', your phone is successfully unlocked.
Enjoy!