My Xperia M phone just updated to 15.4.A.1.9 and I have tried to install some themes, selected themes, then my phone looped in booting up (colourful waves).
You may need to perform a system repair via PC Companion - Switch off your phone and unplug it from your Pc open PCC and run Support zone then select update my phone/tablet then in Blue select repair my phone/tablet and follow the onscreen instructions - At some point you will be asked to connect your phone - To do this hold volume down and connect your USB cable
