This tutorial is to unlocked Huawei USB 3G Modem model E303, E369 and E357 by the used of software and code calculator. Prequisite is the IMEI of the device and also the software you should download first and extract it. You can download the application from here.
Here's few simple steps to be follow:
After you have downloaded the application program, extract it.
Click and run Broadband.exe
Download code writer from here, input your IMEI to generate the code.
Replace the SIM card of your USB modem then plug it to the PC.