From here, you can access "Panel Settings" to fix Mirror Mode or adjust LVDS Map settings.

Different firmware files use different remote control configurations.

The T.hv553.81 is a versatile board, but it requires precision. Always backup your original using a programmer (like the RT809F) if possible before flashing new software.

Here is everything you need to know about finding, choosing, and installing the right firmware for your T.hv553.81 board. What is the T.hv553.81 Mainboard?