I am having Samsung Galaxy S3 I9300XXELLA (O.s JB 4.1.2). Its update not available throught phone. So can I manually download JB 4.3 of I9300XXU. will it work or my phone with I9300XXELLA.
I suggest you to go to http://www.sammobile.com/firmwares/ and search for your device (i9300). There you can see all available firmware versions and download them. Please note that you need to register for an account to be able to see the download links (I don't know why). If you don't like to register you may ask me to send you a specific link.