Sites like ZainabTech or High Tech Info often host firmware archives for various LED TV models, including Onida.
You can check the Onida Innovations page or contact their customer service to see if they can provide the exact firmware for your 55UIB model based on its serial number. Download ONIDA 55UIB Software part04 rar
Press and hold the on the TV (not the remote) and then turn on the main power switch. Sites like ZainabTech or High Tech Info often
While direct official download links for specific archived parts are rarely hosted on the main manufacturer site, they are commonly found on specialized TV repair forums and technical YouTube channels: Download ONIDA 55UIB Software part04 rar
The TV will usually restart automatically once the update reaches 100%. Online Software Update (Alternative)