Extract Huawei E3276s-601 Firmware 21.263.03.00.74 on your computer
Install the Firmware update file for Huawei E3276s-601 downloaded from Huaweiflashfiles.com
Follow the procedure for updating Firmware that is given in Package.

Huawei Flash File | Size: 14.89 MB
Version: 21.263.03.00.74
Operator:Optus Australia
Operating systems: Windows 7/8/10/XP/Vista
Huawei E3276s-601 Firmware Download