Only GSM and LTE after lollipop 5.1.1 update

[Smoson]

Hi folks,

I updated to Lollipop 5.1.1 on my Z3 Compact on Aug 7, 2015.

Since then my phone only connects to LTE (if available) and with GSM (calls/SMS) network. If no LTE but only a lower band would be available (2G, 3G), there is no internet connection at all. This phenomenon is very consistent no matter what I try to change.

I already

(1) turned phone on/off and toggled airplane mode,

(2) checked APN configuration (t-mobile Germany) and tried alternative settings (e.g. toggle IPv4 / IPv6),

(3) checked for network issues or known issues with my service provider with t-mobile.

(4) renewed automatic internet settings from t-mobile

(5) restart in save mode

without solving the issue.

Anybody experiencing the same issue or having reasons or solutions for that?

Cheers,

Smoson

[Qatrium]

Mu suggestion is to try PC Companion Phone Repair if you upgraded over your old version of android without resetting/wiping. This will do a clean installation of the latest firmware and will also wipe your internal memory.

Open PC companion -> Support zone -> Phone/tablet software update -> Repair my phone/tablet (blue link style). Follow the steps given, do not connect your phone until prompted to press volume down while plugging USB cable.
http://www.sonymobile.com/gb/tools/pc-companion/