How to unlock Airtel E1731 (E173Bu-1) Huawei Customised Firmware Modem Dongle :
1. Download E1731 (E173Bu-1) firmware update from the download link which is provided at the end of the article to update your modem with un-customized firmware.
2. After that download Universal master code software from the download link which is provided at the end of the article.
3. Now generate unlock code and flash code using Universal Master code Calculator from Huawei tab.
4. Now plug your Airtel E1731 (E173Bu-1) Huawei customized firmware modem to your laptop / PC and disconnect from the internet.
6. Now firmware update process will start and after a few second it will ask you flash code as your password.
7. Provide the flash code as password.
8. After a few seconds, your modem will be updated successfully.
Now update the modem with latest Huawei Mobile Partner Software from this link.
Note : If your modem does not ask for unlock code then use CardLock Unlock tool to write the unlock code into your modem.
Download E1731 (E173Bu-1) Firmware Update (E1731Update_11.126.15.00.00.B416)