Galaxy S3 I9300 Problems

Hey guys,

I'm from India and I bought the AT&T version, unlocked I think. The build number on the device is JSS15J.I9300ZSENA1. It runs on Android 4.3 Jellybean and is the Pebble Blue version.

I'm using Reliance carrier on it and having frequent call drops, connectivity issues and texting problems as well. Then I get this security notice which asks me to boot the device repeatedly and I don't have any clue why that happens.

Now, my main problem is that I can't use the device for calling purposes as well texting.

So, how can I fix this? When I tried to update the firmware, I found the At&t text on it. That made me think that this might be the right place to post. Anyway, will changing the ROM to a Custom one like Cyanogen help to fix this issue? I need some help with this as I spent some decent bucks on it.

Galaxy S3 gt I9300 Straight Talk bricked

Hello and thanks for looking at my post, I have a straight talk galaxy s3 with a 8gb sd card from straight-talk wireless, I tried to install cyanogenmod (latest) using CWM with the firmware on my phone downgraded to H1 (so I could have root). After this happened, I tried letting the phone charge and seeing what was wrong, I found out 2 things
1) The phone will NOT boot into recovery or anything else, even with a jig
2) The computer makes a sound when I plug the phone in, but I cannot access any of the files
3) Phone is not recognized by ADB
The only light I get from my phone is a solid red light when that only happens when I take the battery out and plug in the phone with a USB(The light is a solid RED)
I do have a read/write tool for micro sd to computer, but I do not know if it would help me, I am at wits end and am very frustrated at this sudden brick, please help if you can.
Any and all help you can give me is well appreciated, thank you in advance, if you need any other information please don't hesitate to PM me or reply.

Best and lastest Recovery for I9300

Hey guys
Pls I need a good recovery for my s3
Right now I have Philz Touch 6.59.0 Recovery with CWM v6.0.5.1
So I need new one cuz when I flash anything it says:
"Using legacy property environment for update-binary
Please upgrade to latest binary"
Thanks in advance

Need Stock Rom for I9300

Hi, all i need stock rom with full instruction to install it plz and if i want to instal a custom rom which one the best coz my phone going slowly and lagy but i need the stock roms or custom rom with Arabic support