Extract the .bin file from your downloaded .rar or .zip archive.

Plug the TV back in and turn on the power. The standby LED should begin flashing rapidly, indicating the update is in progress.

Place the .bin file (often named SI6M181.bin or similar) directly into the root directory of the USB drive. Do not put it in a folder.

Turn off the TV and unplug it from the power source. Insert USB: Plug the flash drive into the TV's USB port.

You can find firmware files (often in .rar or .zip format containing the .bin file) from these community repositories:

RR8501.C031F (related to the C031D and C031A series). Main Chipset: RDA8501.