how to carrier unlock GT-I9300 on 4.3 (easy 6 step)
I find whole forums and also on Google to unlock my galaxy s3 i9300 running on 4.3 but unfortunately there was no solution. All solutions are for 4.1.1 which are very old. Then I did it my self and of course for free. Here are the steps.
1. First root your device by chain fire auto root and insert a sim card.
2. Download twrp manager from play store, open twrp manager and install recovery.
3. Download attached apk file and install it.
4. Open perka's file stash, tap on s3 then modems and modems cwm.
5. Tap 4.3 and download modem_xxugna8.
6. After download go to previously downloaded twrp manager then select install > add zip > select downloaded modem from perka's file tash named folder and flash it. After boot up you should be unlocked.
Don't forget to hit Thanks.