Whenever my 3G change to LTE, my speedtest will maintain at 1mbps dl and 9mbpd ul, no matter where I am and my reception full. To solve it, I need to restart phone in order to get 40mbps.
CSO keep insist its Singapore LTE not stable, but i test my friend note 2 and XY at Singtel hello shop, note 2 doesn't suffer such issues.
But what surprise me is, THEY NEED TWO WEEKS!
I hate comparing diff phone servicing, but 2 weeks is damn long.
iPhone give refurbish set, Samsung 2-3 days and u can request delivery to your door step and Sony? Two weeks.
So Sony user and future XY user, please take note of their servicing.
I don't think is the hardware problem... Looks like more of a software problem.
I got this problem for data when I switch my phone network to auto
as my plan don't have LTE my data connection falls back to 3G takes forever. until I select the phone to 3G network then I resolve the data issue..

