Huawei Y-300 update unsuccessful

[Fasih Shah]

I have rooted my phone and TWRP installed,

The recent update was available at 21st May 2013. I have tried updating it several times downloading it into SD card and internal memory individually.
It requires restart before it can complete the update. As soon as it restarts. The phone automatically boots into TWRP menu. From there i have tried installing the "update.zip" file which fails to "flash".

Can someone provide me a proper solution for this?
Because without important update there will remain some bugs persistent in some apps.

:-\

 

[Fasih Shah]

I also need to know if firmware update is possible if we have rooted any Android.
is there any way i can uninstall TWRP, if returning to stock is the only option please guide me the specific steps to do that.