I am afraid this not is going to be a short and easy story... I will try to be short
After the Stock update to 4.4.2 i got finally fed up with the fact that the long awaited KitKat drains battery like a power addict and decided to go back to stock 4.2.2 - which, for me, solves two problems - in this version the Bluetooth connectivity in my car works properly and the battery is used more 'soberly' as well as that I can easily root it and clear all the bloatware.
I found several stock versions of 4.2.2 - e.g. C6603_10.3.1.A.0.244_Generic NCB.ftf, C6603_10.3.1.A.0.244_CE.ftf, C6603_10.3.1.A.2.67_CE.ftf
After flashing them with the latest flashtool everything seems fine - battery, bluetooth,wifi etc. BUT the mobile data has the following problem: the phone connects to 4G, 3G and GPRS, but apart from Youtube none of the applications is able to use the Internet connection from the mobile operator. This to me seems like a problem with DNS resolution but I do not have any firewalls etc. installed or activated.
It may be worth mentioning that when Chrome tries to connect to a web address (e.g. xyz) for an instant there is a message on the screen "Redirecting you to xyz web address", maybe this is the place where it goes wrong? Needles to say that the connection to the specified website is not possible because "Chrome could not find the xyz page"... (this does not happen on wifi connection).
I would be very grateful if U could suggest a way out !