How to Unlock Huawei Airtel E173CS-1 Free – I have already provided the article about how to flash Airtel Huawei E173CS-1 latest firmware and how to generate 86 series IMEI unlock code. But, recently when I was unlocking some Airtel Modem, a few modems was asking for unlock code while putting another SIM on the modem but some of them was not asking for unlock code. Hence, we are proving the article for those modems who does not ask for unlock code after flashing the modem also.
Step by step guide to unlock Huawei Airtel E173CS-1 Free :
1. After flashing the airtel E173CS-1 modem download the Huawei Modem Code Writer Tool from the link provided below after the article.
2. Extract the zip file and run the HUAWEI MODEM Code Writer.exe.
3. Now plug your flashed airtel modem in your computer.
4. Now click on “Please Select Com Port” button and it will open a small window.
5. Click on Detect button and select the port.
6. After selecting the Com port click on Accept button. 
7. Now click on Unlock Modem button.
8. Now its will open a new windows asking for unlock code.
9. Here, provide the Unlock Code (8 digits) which you have generated via this article and after that click on OK button.
Now you have a unlock Airtel 3G modem in your hand. Enjoy.