Help: Need Huawei UMG1831 Firmware


masoom kameena!
Random 3G!
Dear All,I need Huawei umg1831 firmware version 11.826.03.01.420, i have upgraded it with the latest firmware downloaded from T-Mobile website, but I after successful update device is getting frequent device disconnection(removed from windows) problem.A strange solution i have discovered to avoid disconnection is by creating a dial-up connection with Huawei 3G Modem, its working like charm but when trying to connect with Mobile partner its getting disconnected :unsure:I want to rollback with the older version of firmware, i have googled but failed to find the above version :(Any positive help is appreciated :)