Extract Huawei E303s firmware 21.157.31.00.850.B757 on your computer
Install the firmware update file for Huawei E303s downloaded from Huaweiflashfiles.com
Follow the procedure for updating firmware that is given in Package.

Huawei Flash File | Size: 7.05 Mo
Version: 21.157.31.00.850.B757
Operator: Aircel India
Operating systems: Windows 7/8/10/XP/Vista
Huawei E303s Firmware Download