xperia m Updating error 15.5.a.1.5

[Bad_Guy]

Hey guys
I tried to update my phone but in the middle of installing the phone got turned on and i got this error: could not install the update
i tried again and the same thing happend.
Help plz

[Thommo · Accepted solution]

You need to perform a system repair - This will factory reset your phone

Switch off your phone and unplug from Pc (Hold volume up and power for around 10 seconds)
Start PC Companion and select Support zone then Update my phone/tablet then in Blue Repair my phone/tablet and follow the onscreen instructions - When prompted connect your phone still switched off holding volume down or back button - This should start the repair or reformat process

If you are using Windows 8/8.1 or a 64bit operating system then adjust the settings for PC Companion and run in compatibility mode and chose Windows 7 or XP

[Bad_Guy]

Hey guys.
I wanna update my device. But every time In the middle of Installing update the phone turns on and says The update didn't install.
What's the problem?
I need this update badly.
Thanks