I had received an update to 5.1 lollipop on my Xperia T2 Ultra. I downloaded it, started the upgrade, and waited. But they said the update failed. Please try later. And I tried it time and again. Then I thought it must be some default issue. So I reset my phone. But then, the update itself disappeared, and I couldn't download it or do anything. I'm still stuck on Kitkat and my phone is very laggy. Please help....
