Hello, it’s already solved, but I wanted to share something with you. My Xperia 10 plus was most of the time stuck in a bootloop, after the notification of the 4.4.0.64 update (I updated to Vanha Rauma before, so this was a minor bump). I could stop the bootloop and let the device stay off with pressing the volume up and power button for x seconds (three vibrations). On some occasions, I was able to boot and log in, resulting in a automatic reboot in no time.
I finally discovered that having the device on the charger, stopped the bootloop for whatever reason. So I kept it for some days like that and eventually connected to a computer (without rebooting when detached from the charging cable), backupped as much as I could and performed the latest update. Now it seems to be ok again. Does anyone has a clue what happened to the Xperia 10 plus, resulting in a bootloop?