HD2 SIM Unlock - bibanon/android-development-codex GitHub Wiki
Notice that you can only unlock your phone from within stock Windows Mobile 6.5. If there is even the slight chance that you will use any carrier other than the one your HD2 is shipped with, it is strongly recommended to SIM unlock your phone.
It will suck to take the long road back to WM6, so it's best to make your decision now.
Some carriers will give you the unlock code for free, and others will not. If you have money to spend, you can easily get unlock codes for a small sum. Below are some good sites for codes. Follow the instructions on their site to unlock your HD2.
- UnlockUSA, gives unlock codes for $4.00
- http://www.pdamagician.com/unlocking.html
- http://unlock-now.com/
- http://leo.unlock-now.com/
Once you unlock your phone, it is permanently unlocked, and nothing short of hardware modification can ever change that.