This trick is tested by me on my huawei E1550 modem and its work perfectly.
Follow below step to unlock modem :-
1) First Download this firmware. CLICK HERE TO DOWNLOAD
This is password protected site. The password is www.shaikhtrickz.blogspot.com
2) Then Go to www.a-zgsm.com/huawei.php
3) Enter your huawei modem IMEI no. & enter security code besides shown. and then click Generate.
4) Now you will get your Unlock code and Flashing code. Just note down both code.
5) Now insert you modem into PC. wait for detecting. (insert modem without SIM).
6) Now close all process of idea net setter and idea net setter manager. Also close from tray.
7) Now open downloaded firmware and install it. When you installing it ask for password.
8) Just enter your flashing code there and click continue.
9) when installing done means you successful to unlock the modem.
10) now open iden net setter software from desktop and it ask for password. Here enter your unlock code.
Now that's it.