UNO Rev 3 Upload Error "avrdude: stk500_getsync(): not in sync"

Arduino UNO started giving upload problem. Earlier it was working fine. Changed driver windows cable etc etc etc but no reponse after 10 attempts it fails.

Checked loop-back test working fine so COM is prefect only problem with sketch upload. Tried pressing reset button but no use.

L Led ON RX Blink during upload TX does not blink during upload.

The bootloader may be gone. Or you have the wrong board chosen in the IDE.

Have you tried with a different computer? Different version of the IDE?

Tried everything. Another board works fine on same cable and PC

So try to upload the bootloader.