I have previously shared also various types of firmware update. Firmware and Software of Tele2 Huawei Modem Dongle can be downloaded from this article. Firmware and Dashboard Update of M1 Mobile Broadband Singapore can be downloaded from here. Firmware of Huawei E3272 modem can download from this article.
Optus Huawei E1762 USB Modem
Download Firmware of Optus E1762 Dongle (Download Firmware E1762update_11.126.08.03.74.b416.exe)
Optus Huawei E160E USB Modem
Download Firmware Update of Optus E160E USB Modem (E160E_update_11.609.10.02.432.b418.exe)
Optus Huawei E169 USB Modem
Optus Huawei E220 USB Modem
Download Software Update of Optus E220 USB Modem (For Windows and Mac)
Optus Huawei E870 Data Card
Download latest Firmware for Optus E870 (e870update_11.304.20.00.00.b310.zip)
Download latest Software Update for Optus E870 (Windows & Mac PC)
Unlocking of Optus Huawei E1762 USB Modem, Optus Huawei E160E USB Modem, Optus Huawei E169 USB Modem, Optus Huawei E220 USB Modem, Optus Huawei E870 Data Card is easy. Just put an unacceptable sim in your Modem and plug it to PC. Now it will ask you unlock code. Put correct unlock code and your modem will be unlocked forever.
Users who are facing the problem in putting the unlock code can use Huawei Code Writer Software from this link.
For process how to update the firmware of USB modem you can refer this article.
Update : Additional Huawei firmware download links :
Firmware E169Update_11.315.05.00.00.B418.zip (7.2MBPs Enabler)