You can unlock your LG U400 phone from network lock using unlock code.Unlock code is the best and safest way to unlock phone.You can get the unlock code for your phone from your Network service provider or any third party online vendors like http://www.superunlockcodes.com/lg-u400/rs16wp9/ here you need to specify your country,Network name to which it is locked,IMEI number of your phone.Then they deliver unlock code to you through mail with unlocking instructions.By using this you can unlock your phone easily.
sahana
August 2013
Sorry to burst your bobble but there is no such free solution to unlock your phone.
You can find plenty of "patchers" applications but if you do not understand the process you could damage your phone permanently.
Best advise is to go to your local mobile repairs shop and have it done professionally.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix mobile phones.