Some users of Huawei Airtel E173U-1 modem getting problem after unlocking the modem. After getting modem unlocked also, after changing the SIM message comes as invalid sim. Users who are facing the problem should first flash his modem with the latest firmware version of huawei E173U-1 usb 3g modem update. The lastest version firmware for Huawei E173U-1 can be downloaded for free from the link which is provided at the end of the article. Users can upgrade to the latest version if you have any problems using the modem with old firmware. The said firmware will also help those users whose modem is not working properly.
Step by step guide to update the firmware of Huawei Airtel E173U-1 :
1. Double click on the downloaded exe file and and accept the terms and conditions to go ahead.
2. Click and next and its will search for your modem. After the search and detection of modem is complete the update asks for confirmation.
3. After a few minutes it will update your E173 modem to latest firmware.
Note : Before proceeding to the above steps make sure that you have much backup in your ups. Because a power break can make your modem forever dead.
After updating the firmware you can now unlock your modem through normal procedure using Huawei modem code writer tool or Cardlock Unlock tool.