After the update to 4.1.2, my xperia j is having so much problems, the volume key and power key go irresponsive. some time network shuts off. Please help me out as early as possible.. Its irritating.
First try making a repair of the phones software using PC Companion and then try the phone for a few days without any apps and see if the problem remains. If so i recommend that you contact a service location or local Sony Xperia support (http://www.sonymobile.com/global-en/support/contact-us/) for assistance.
Please note that a repair in PC Companion will delete all data in the phone so first make a backup of things you want to save.
