If you are looking for that specific version 198, I can help you:
Firmware updates for TCL TVs with the V8-S68AT02 chipset are frequently hosted on tech support sites and forums dedicated to TV repair, such as . Download S68AT02 LF1V198 part03 rar
It is not a part of a multipart .rar archive, but rather a large .bin firmware update file. If you are looking for that specific version
the USB into your TV (use the USB 2.0 port if possible). Unplug the TV from power. Download S68AT02 LF1V198 part03 rar
the downloaded file (e.g., V8-S68AT02-LF1V198.bin ) directly to the root of the USB drive.