shv-e210L drop calls 80 char SMS

[jcboi]

hi good day. i just bought a korean variant S3 from a friend and i didnt know of the problems already in the unit..
i just learned that drop calls and the short sms capacity of the model will be a problem..plus the various korean aps and pop ups that,of course, i do not understand... can anyone please help me on what to do to fix it...i was advised custom ROM but im finding it hard to to a back up of my files..all my files are very important for work especially the contacts and sms.....and is it true that ill be getting better signal if i do the customized ROM??i already downloaded ODIN and honestly its my first time to try it so i really want everything crystal to me before i start doing what i need to do... thank you very much to those who will find time to help..godbless

 

[jcboi]

someone advised me to do this

HOW TO: Install Galaxy S3 SHV-E210L KLJLL5 Android 4.1.2 Jelly Bean Firmware - Tutorial / Guide

and my phone wont open now..after the installation is complete.it just stays on the start up screen and doesnt continue to show the homescreen.. please help me with this

 

[GSDer]

1. Click on ?PDA? and select file with ?CODE? in its name.
2. Click on ?Phone? and select file with ?MODEM? in its name. Ignore this step if there is no such file.
3. Click on ?CSC? and select file with CSC? in its name. Ignore this step if there is no such file.
4. Click on ?PIT? and select the .pit file. Ignore this step if there is no such file.
When you used Odin did you do all 4 of the above steps, or just certain ones? Can you still boot the phone in Download mode?

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