The indicator light (usually red/blue) will start blinking rapidly. This indicates the software is being installed.
Copy the correct firmware file (often named bin_8501.bin ) directly to the root of your USB drive. Do not put it in a folder. Download RR8501 C031A V60 All Resolution rar
To fine-tune settings or flip the image, you can often enter the service menu by pressing Menu + 1147 or Input + 2580 on the remote. The indicator light (usually red/blue) will start blinking