If your TV still has internet access, try the official route first:
Select to check for available official packages from TCL. Key Specifications for LED40S4900 Go to product viewer dialog for this item. Download TCL LED40S4900 Firmware part1 rar
The firmware for this model is typically split into parts (like "part1.rar") because of large file sizes. Before proceeding, verify your specific hardware: TCL LED40S4900 Go to product viewer dialog for this item. If your TV still has internet access, try
Use a tool like WinRAR or 7-Zip to extract "part1.rar." This will automatically pull data from other parts to create a single file, usually named Update.img or SW BIN . Flash the TV: Power off the TV and unplug it from the wall
Copy the extracted file directly to the root directory of your FAT32 USB drive. Flash the TV: Power off the TV and unplug it from the wall. Insert the USB drive into the TV's USB port.
Finding the firmware for older TV models like the TCL LED40S4900 Go to product viewer dialog for this item.