How can I change my rom in my Samsung Galaxy S3 i9300?

[AC Question]

how can i change my rom in samsung galaxy s3 i9300

my galaxy s3 i9300 won't boot stack on Samsung galaxy s3 logo and when i connect it to a computer always show usb not recognized while all drivers are installed any one know alternative way to change rom.

 

[AlphaTango414]

Re: how can i change my rom in samsung galaxy s3 i9300

Hello and welcome to Android Central!

Is your device currently rooted?

 

[PRINCE540]

Re: how can i change my rom in samsung galaxy s3 i9300

yah is rooted before stack

 

[PRINCE540]

Re: how can i change my rom in samsung galaxy s3 i9300

i tried to install CWM bt it fail on signature verification

 

[AlphaTango414]

Re: how can i change my rom in samsung galaxy s3 i9300

Do you have any custom recovery installed? Such as TWRP?

Did you not make a backup before doing anything after gaining root privileges?