For further assistance, you can also check community resources like the Hisense Reddit archive for alternative firmware versions.
Go to the Hisense Firmware Download portal and enter your TV's Serial Number to get the correct version for your specific panel.
Place the upgrade_loader.pkg (or similar) file into the root directory of the USB.
If the website does not list your model, contact Hisense Support directly. They can provide a direct download link or mail a USB drive with the correct firmware. How to Install via USB