Share your experience!
can anybody tell about downgrade 4.2.2 to 4.1.2 for xpera L COZ i face so many problem after upgrade plz help
You can flash 4.1.2 .ftf through flash tool. download it, unlock your boot loader and flash it from flash tool.
Manually downgrade will void your warranty. if you don't wanna lose warranty, take it to a service center.
thank you so much 
where can i gat flashtool ?
Guide how to unlock bootloader?
http://forum.xda-developers.com/showthread.php?t=2332900
Guide: how to flash rom via flash tool?