The stock nandroid backup (M020) can be found here
C811_stock.rar
If you want to revert stock apk's just adding them woun't do. You'll have to install them as system app.
The call fix is updated and now does not require system file modifications. Read the corresponding thread for details.
Note that if you install C811_stock that does not mean you can safely update.
You will still have the CWM you had and root. And this backup does not restore baseband.
Also this backup has non-working camera. If you want to use it and need a fix tell me.