S3 Soft bricked... How to fix without connecting computer

Hi guys, I have a soft bricked i9300 which doesnt go past the samsung logo. It can go into download and recovery mode. Ive tried wiping cache and factory reset etc with no joy. Ive tried to connect to odin and kies but neother detect the phone and ive spent endless days trying to sort what looks like a drivers issue but to no joy. Im now wondering if theres another way to unbrick without connecting to the computer. I noticed i have options such as update from external storage, and adb sideload and im wondering if i can use this somehow fix the phone. Please please help me. I dont know what android version the phone is btw but i know it was never messed with software wise. It just went bricked one day.