i'm also on EE UK (orange) and face the same problem with my phone too. I used to be able to get strong 3G or H in my area, but just a few days back, it dropped down to a single bar of 2G (E) and then disconnects off the network. Tried resetting the phone, reflashing firmware, updating to EE portico firmware and then downgrading as well, but not working, now i can't restore from my MS account because there's no internet connection. masive fail
What's wrong with WiFi to restore your account?
Also, why did you reflash Portico!? You just invalidated your warranty if you're in the UK, what with the fact that Nokia haven't released an officially supported version of Portico outside of ATT and Rogers users yet...
