Some factory pac files here except A278t_S162_121214.20130814_multilang.pac which one is compiled by me using factory components + backuped boot (unlocked) and system partition. That one is rooted and multi-lingual, tested and works perfectly. The other three versions has not been tested by me but they are factory files. According to my experience, different versions are interchangable, no HW issues can be happened.
These pac files can be flashed by the provided flasher application, they are NOT recovery update files.
Guide for ResearchDownload: http://forum.xda-developers.com/showthread.php?t=2624918 (Thank you Ravage32)
Additional recommendations: 1. If you make a full flash upgrade (all available items are checked on the 'Main Page') and in that case only, to avoid the stuck of the flashing process, check 'Erase All Flash' on the 'Flash Operations' page. 2. If you flash a totally dead/erased/badly flashed phone, then uncheck 'NV' in the 'File Backup' section on the 'Backup' page.