Extract Huawei E303Ms-2 firmware 21.158.00.01.103.B757 on your computer
Install the firmware update file for Huawei E303Ms-2 downloaded from Huaweiflashfiles.com
Follow the procedure for updating firmware that is given in Package.

Huawei Flash File | Size: 8.27 Mo
Version: 21.158.00.01.103.B757
Operator: Swisscom Switzerland
Operating systems: Windows 7/8/10/XP/Vista
Huawei E303Ms-2 Firmware Download